An overview of recent taxonomic studies on Euphorbiaceae s.l. in Brazil

Panorama dos recentes estudos taxonômicos em Euphorbiaceae s.l. no Brasil

ORIGINAL PAPERS

An overview of recent taxonomic studies on Euphorbiaceae s.l. in Brazil

Panorama dos recentes estudos taxonômicos em Euphorbiaceae s.l. no Brasil

Ricardo de S. Secco^I; Inês Cordeiro^II; Luci de Senna-Vale^III; Margareth F. de Sales^IV; Letícia Ribes de Lima^V; Débora Medeiros^III; Bárbara de Sá Haiad^III; Arline Souza de Oliveira^III; Maria Beatriz Rossi Caruzo^II; Daniela Carneiro-Torres^VI; Narcisio C. Bigio^VII

^IMuseu Paraense Emilio Goeldi, Av. Magalhães Barata 376, 66040-170, Belém, PA, Brazil

^IIInstituto de Botânica, C.P. 3005, São Paulo, SP, Brazil

^IIIMuseu Nacional, UFRJ, Quinta da Boa Vista, São Cristóvão, 20940-040, Rio de Janeiro, RJ, Brazil

^IVUniversidade Federal Rural de Pernambuco, 52171-900, Recife, PE, Brazil

^VUniversidade Federal de São Carlos, Araras, SP, Brazil

^VIUniversidade Estadual de Feira de Santana, 44031-460, Feira de Santana, BA, Brazil

^VIIUniversidade Federal de Rondônia, Depto. Biologia, Campus BR 364, km 9,5 Sentido Acre, 78900-000, Porto Velho, RO, Brazil

ABSTRACT

The Euphorbiaceae sensu lato are distributed mainly in the tropics, in various types of vegetation and habitats, being one of the largest, most complex and diverse families of angiosperms. It has recently been divided into four families, according to classification systems based on molecular phylogeny: Euphorbiaceae sensu stricto, Phyllanthaceae, Putranjivaceae, and Picrodendraceae. There is a proposition to establish Peraceae still under discussion. There were also changes in the taxonomic position of genera widely distributed in the Brazilian territory, such as Amanoa, Drypetes, Pera, Phyllanthus, Podocalyx, Pogonophora, and Richeria, among others. In addition, new species have been proposed and the limits of taxa distribution are expanding in Brazil. Thus, the authors provide an overview of recent studies and advances in the taxonomy of Euphorbiaceae s.l. in the Northern, Northeastern, Southeastern and Southern regions of Brazil, concentrating on review works and regional floras, as well as the changes that resulted in setting a new taxonomic family.

Key words:Croton, Phyllanthus, taxonomy of Phanerogams, plant distribution.

RESUMO

As Euphorbiaceae sensu lato distribuem-se especialmente nos trópicos, nos mais variados tipos de vegetação e habitats, sendo uma das maiores, mais complexas e diversificadas famílias das Angiospermas. Foi recentemente dividida em quatro famílias e segundo os atuais sistemas de classificação, baseados em estudos filogenéticos envolvendo dados moleculares, está assim classificada: Euphorbiaceae sensu stricto, Phyllanthaceae, Putranjivaceae e Picrodendraceae, havendo uma proposição de estabelecer Peraceae, táxon ainda em discussão. Houve também mudanças no posicionamento taxonômico de gêneros de ampla distribuição no território brasileiro, tais como Amanoa, Drypetes, Pera, Phyllanthus, Podocalyx, Pogonophora e Richeria, entre outros. Além disso, novas espécies vêm sendo propostas e a amplitude dos limites de distribuição de diversos táxons vem aumentando no Brasil. Diante do exposto, os autores fornecem um panorama geral dos estudos mais recentes e avanços na taxonomia de Euphorbiaceae s.l. nas regiões Norte, Nordeste, Sudeste e Sul do país, concentrando-se nos trabalhos de revisão e floras regionais, bem como nas mudanças que resultaram em nova configuração taxonômica da família.

Palavras-chave:Croton, Phyllanthus, taxonomia de fanerógamos, distribuição de plantas.

Introduction

The Euphorbiaceae is composed of 334 genera (Webster 1994) and over 8,000 species (Radcliffe-Smith 2001), which are distributed mainly in the tropics in the several types of vegetations and habitats. It is one of the most complex, large and diverse families of Angiosperms. Wurdack et al. (2004) consider Euphorbiaceae sensu lato as a pantropical family, composed of 340 genera and approximately 8,000-9,000 species.

This family is considered as one of the most important Angiosperm groups, especially for comprising genera such as Hevea Aublet and Manihot Miller. According to Schultes (1987), the rubber-tree (Hevea brasiliensis (Willd. ex A. Juss.) Muell.Arg.) has drastically changed human life within a single century, because it is a natural source of rubber, whereas the manioc, also known in Brazil as "aipim", "macaxeira" or "cassava", (Manihot esculenta Crantz) is among the 13 most important human foods.

Many authors studied the taxonomy of this family, standing out Jussieu (1824), Baillon (1858), Bentham (1878, 1880) Mueller (1873), Hutchinson (1969), Jablonski (1967), and Pax & Hoffmann (1914, 1931). Recently, a significant contribution was made by Webster (1975, 1987, 1994), which was mainly related to the family's classification and to a revision of members of the Euphorbiaceae in the New World (Webster 1993; Webster & Armbruster 1991).

Recently, the family has been through several taxonomic changes, mainly based on phylogenetic studies with molecular data (APG II 2003; Wurdack et al. 2004, 2005; APG III 2009), with marked differences in relation to the traditional classification revised and proposed by Webster (1994), in which Euphorbiaceae was divided into five subfamilies.

However, although the Euphorbiaceae s.l. have been studied by a group that comprises botanists from several countries, including Brazil, and carries out research in taxonomy, anatomy, phytochemistry, economic botany, and molecular systematic, which already resulted in the division of the family into four (APG II 2003), the knowledge of this family still has considerable gaps, even regarding morphology. Webster (1987) emphasizes that to propose a safer classification for this family, at least detailed morphological and anatomical studies involving many of its genera are required.

This situation is also observed in Brazil, where many genera of Euphorbiaceae s.l. exhibit high number of species, such as Phyllanthus L., Mabea Aublet, Dalechampia Plumier ex L., and Croton L. These genera still have confusing and outdated taxonomy in some regions of the country, though some advancements have been made in the past years, mainly with the publication of the Species List of the Brazilian Flora (Cordeiro et al 2010; Secco et al 2010).

Therefore, the present study aims at presenting an overview of the most recent studies on Euphorbiaceae s.l. in four Brazilian regions as well as changes in the classification of the group, and at pointing out research opportunities that could lead to a more complete knowledge, in particular of the less studied genera.

Euphorbiaceae Systematics in the Light of Modern Classification Systems

In Engler's system (1964) the Euphorbiaceae were classified in the class Dicotyledoneae, subclass Archychlamydeae, order Geraniales and suborder Euphorbiineae.

Cronquist (1981) classified them in the class Magnoliopsida, subclass Rosideae, order Euphorbiales.

Webster (1975) proposed an infrafamiliar classification for the Euphorbiaceae, subdividing it into five subfamilies, which were separated into two groups, according to the number of ovules per ovary locule: Phyllanthoideae and Oldfieldioideae, both with two ovules and Acalyphoideae, Crotonoideae and Euphorbioideae, with one ovule.

In a revised and extended classification, Webster (1994) proposed that Euphorbiaceae s.l. encompasses five subfamilies: Phyllanthoideae, Oldfieldioideae, Crotonoideae, Acalyphoideae, and Euphorbioideae. He also proposed new tribes and subtribes in the same study.

However, according to the classification system proposed by the Angiosperm Phylogeny Group (APG II 2003), there are no molecular evidences that allow maintaining Euphorbiaceae s.l. as a single group. The family was then divided into four: Euphorbiaceae sensu stricto, comprising the subfamilies with uniovulate ovary locules (Euphorbioideae, Crotonoideae, and Acalyphoideae); Phyllanthaceae, including the Phyllanthoideae (biovulate ovary locules), Picrodendraceae, including the Oldfieldioideae (biovulate ovary locules) and Putranjivaceae (biovulate ovary locules, comprising Drypetes Vahl and Putranjiva Wall.).

Wurdack et al. (2005), using molecular data of the plastidial regions rbc-L and trnL-F, assessed the circumscription of Euphorbiaceae s.s. (Acalyphoideae, Crotonoideae and Euphorbioideae), as well as the monophyletism of the suprageneric taxa recognized in recent classifications. Hence, they proposed two new subfamilies in Euphorbiaceae s.s.: Peroideae and Cheilosoideae. These studies corroborated the findings of the Angiosperm Phylogeny Group (APG II 2003), i.e., only the subfamilies with uniovulate ovary locules (Euphorbioideae, Acalyphoideae and Crotonoideae) are considered as Euphorbiaceae s.s.; they re-established Peroideae Baill. ex Hassk. as a subfamily and admitted that the classification of Euphorbiaceae s.s. needs revision.

Euphorbiaceae s.s. and the other families segregated from Euphorbiaceae s.l. are included in Malpighiales, according to the Angiosperm Phylogeny Group (APG II 2003; APG III 2009), Wurdack et al. (2005) and Wurdack & Davis (2009). Hence, it was necessary to move some genera to independent families, as for example, Amanoa Aublet (to Phyllanthaceae), Podocalyx Klotzsch (to Picrodendraceae), and Drypetes (to Putranjivaceae). Those changes have been debated and have not always received the approval of specialists in Euphorbiaceae, as in the case of Pera Mutis, in Peraceae, which still needs further studies according to APG III (2009).

This division of Euphorbiaceae s.l. into four families was maintained by the Angiosperm Phylogeny Group (APG III 2009), which stated also that the recognition of Peraceae Klotzsch would be necessary to maintain Euphorbiaceae as a monophyletic group, since Rafflesiaceae would be placed between the subfamilies Peroideae and Acalyphoideae. Yet it would depend on future studies, what would hinder the tentative establishment of the family (Peraceae).

Judd et al. (2009) recognized four families: Euphorbiaceae s.s., Phyllanthaceae, Picrodendraceae, and Putranjivaceae, all in the clade Malpighiales; Phylanthaceae exhibits two ovules per locule and seeds without aril. Picrodendraceae also has two ovules per locule, but it does not have divided styles and nectariferous disk.

Wurdack & Davis (2009) proposed the elevation of Peroideae to the family status (Peraceae). Although approved by the APWeb, this proposal is still under debate (Stevens 2001). Reveal & Chase (2011) did not consider Peraceae as a family, considering it as a synonym of Euphorbiaceae.

Geographic Distribution of Euphorbiaceae

Euphorbiaceae s.s. has pantropical distribution, with higher occurrence in tropical regions. According to Judd et al. (2009), this family is composed of 222 genera and 6,100 species. These authors state that Phyllanthaceae has predominantly tropical distribution, with 55 genera and 1,745 species. According to Souza & Lorenzi (2008), Picrodendraceae is a pantropical taxon and has approximately 30 genera and 100 species, and Putranjivaceae is predominantly paleotropical, with only three genera and approximately 200 species.

Wurdack & Davis (2009) stated that Euphorbiaceae s.s. is the largest Malpighiales family, with more than 246 genera and approximately 6,300 species.

Euphorbiaceae Studies in Brazil

Croton L. is the most studied genus of Euphorbiaceae s.l. in Brazil and abroad, not only from the perspective of classic taxonomy, but also of phylogenetic systematics made mainly with molecular data. Complex genera such as Phyllanthus, Dalechampia, Manihot, and Mabea still need updated taxonomic revision, aiming at a better knowledge of their species boundaries.

Next, we provide a general overview of what has been studied on the matter by different research groups in Euphorbiaceae s.l. in the northern, northeastern, southeastern, and southern regions of Brazil.

I. Euphorbiaceae in the Northern Region

In the Brazilian Amazon, pioneer studies were led by Jacques Huber, Adolpho Ducke, and Walter Egler, with contributions by Murça Pires and William Rodrigues. From the 1980s on, there has been great increase in Euphorbiaceae research in the region, mainly involving the subfamily Crotonoideae (sensu Webster), starting with studies by Secco (1985), discussing varieties of Sagotia racemosa Baill. Secco (1987) assessed systematic and evolutionary aspects of Sandwithia Lanj., and compared them with those of Sagotia Baill. and Anomalocalyx Ducke. Secco (1988) described the second species of Sandwithia, S. heterocalyx Secco, an uncommon taxon that exhibits a pistillate flower with free calyx, contrary to the genus' pattern.

In the 1990s stands out the study by Secco (1990a), who revised Anomalocalyx, Dodecastigma Ducke, Pausandra Radlk., Pogonophora Miers ex Bentham, and Sagotia, providing a consistent update of Pausandra, a genus with very confusing taxonomy until then, in particular because of its sparse distribution in the Amazon and its little conspicuous, usually deciduous flowers. The revision of Richeria Vahl (Secco & Webster 1990) invalidated the varieties proposed previously for R. grandis Vahl, as well as updated the synonymy. Patterns of geographic distribution of some Crotonoideae in the Amazon were presented by Secco (1990b; 1993a), who assessed mainly Pausandra species and started a study on Croton species that occur in the Brazilian Amazon. In his study, he described some liana species, comparing them with C. pullei Lanj., whose palynological aspects continued to be discussed by Carreira et al. (1996). A taxonomic treatment for Nealchornea Huber was made by Secco (1997).

Starting the studies on Alchorneae (Hurusawa) Hutchinson, Secco (1993b) proposed the species Alchornea fluviatilis Secco, collected in the Carajás Mountain Range (state of Pará) and in the Pindaré River (state of Maranhão); the species is uncommon in the genus because it is monoecious. Later, analyzing collections from Bolívia, he described Alchornea anamariae Secco and proposed a new combination for Alchornea Swartz, based on Conceveiba pubescens Britton, later renamed as Alchornea brittonii Secco. This research resulted in a revision of the Neotropical Alchorneae, published in Flora Neotropica (Secco 2004a), updating Aparisthmium Endlicher, Alchornea, and Conceveiba Aublet, resulting in a total of 37 species. Next, Secco & Giulietti (2007) discussed aspects of the biology of Conceveiba guianensis Aublet collected in the Mocambo Reserve (Belém, Pará), in which only individuals with pistillate flower, fruits, and seedlings were found.

An update of the taxonomy and phytogeography of Hevea was proposed by Pires et al. (2002). Taxonomic treatments were also made for Alchorneopsis Muell. Arg., Cleidion Blume and Polyandra Leal (Secco 2001), Adenophaedra (Muell. Arg.) Muell. Arg., and Tetrorchidium Poeppig (Secco 2003), as well as for 15 Euphorbiaceae genera of the Ducke Reserve (Secco 2005). In addition, other studies on Euphorbiaceae present in Neotropical floras are Flora of Venezuelan Guiana (Secco in Webster et al 1999), Flora of the Ducke Reserve (Secco & Cordeiro 1999), Checklist of Flora of Acre (Secco et al. 2008b), Checklist of the Plants of the Guiana Shield, Checklist of Flora of Bolivia (Secco et al. in press), Euphorbiaceae of the Flora of Caxiuanã Reserve (Trindade & Secco 2009), and Rare Plants of Brazil (Secco & Rosário 2009). A taxonomic update of the rubber-tree Hevea brasiliensis was made by Secco (2008a), by requested of EPAMIG (Agricultural Research Company of Minas Gerais).

Secco (2008b) concluded the revision of Croton species that occur in the Brazilian Amazon, including most of those addressed by Mueller (1873) and bringing about taxonomic novelties such as Croton faroensis R. Secco, C. dissectistipulatus R. Secco (Secco 2004b), an uncommon species because it has only three stamens, C. subasperrimus R. Secco, P. Berry & C. Rosário, C. diasii Pires ex Secco & P.E.Berry, and C. trombetensis Secco, P.E.Berry & N. Rosa. He also recorded new occurrences in the region, such as Croton gossipiifolius Vahl, Croton nervosus Kl., Croton sampatik Muell.Arg., C. guianensis Aublet, C. spiraeifolius Jabl., C. urucurana Baill., C. draconoides Muell.Arg., C. mollis Benth., C. tessmannii Mansf., and C. schiedianus Schl. Guimarães & Secco (2009) updated the species of Croton section Cyclostigma and Croton section Luntia subsection Matourense (Euphorbiaceae s.s.) that occur in the Brazilian Amazon by including Croton urucurana Baill., C. draconoides Muell.Arg., C. trombetensis Secco; Berry & Rosa, C. sampatik Muell.Arg., C. palanostigma Kl., C. pullei Lanj., and C. matourensis Aublet.

Currently, Euphorbiaceae research in the Amazon is focused on Pera (see Bigio & Secco 2012, in this volume), a genus which had never before been subjected to revision, and which still has a confusing and outdated taxonomy, in addition to Micrandra Bentham, Dalechampia and Amanoa.

Pera is a Neotropical taxon of the subfamily Acalyphoideae, with ca. 30 species distributed from Cuba and Central America to southern Brazil, and highest diversity in the Amazon (Webster 1994). It is the only member of the tribe Pereae (Klotz. & Gcke.) Pax & K. Hoffmann, a position supported unanimously by many who have made treatment to the genus (Baillon 1858; Pax & Hoffmann 1919; Jablonski 1967; Webster 1994). It exhibits a unique morphological character among the Euphorbiaceae: the unisexual pseudanthia (cymose inflorescence), with reduced flowers involved by a showy involucral bract (yellow, cream, white or sometimes red), which is fragrant and more or less globose. The most recent studies were published by Gillespie & Ambruster (1997), comprising only 5 species from the Guianas, and by Webster et al. (1999), comprising 6 species included in the Flora of Venezuelan Guiana. In Brazil stands out the study by Leal (1951), who proposed some new species. Bigio (2009) made a taxonomic treatment of 13 species from the Brazilian Amazon. Recently, two new species were proposed: P. manausensis Bigio & Secco (Bigio & Secco 2010) and P. eiteniorum Bigio & Secco (Bigio & Secco 2011).

Molecular systematics led to great advancement in studies on Euphorbiaceae. However, morphological characteristics hinder the insertion of some genera in this family, as it is the case of Pera, which exhibits inflorescences inside an involucral bract, and its flowers and floral parts in the pseudanthia. By having this inflorescence type, Pera is similar to Dalechampia, though the latter belongs to Euphorbiaceae s.s.

Micrandra is an example of an Amazonian genus that needs revision. According to Webster (1994), it is composed of seven species, and belongs to Euphorbiaceae, subfamily Crotonoideae, tribe Micrandreae, subtribe Micrandrinae, together with Cunuria Baillon and Micrandropsis Rodrigues. According to APG system (APG III 2009), Micrandra would be subordinated to Euphorbiaceae s.s. The most recent study on this genus remains Schultes (1952). Therefore, the genus needs revision, though Berry in Webster et al. (1999) provided a synopsis of its species in the Flora of the Venezuelan Guiana.

Schultes (1979) published additional notes on Micrandra, focusing the economic potential of the genus, especially as a source of latex for rubber production. It is important to revision this genus, especially because of the close relationship that it has with Cunuria, which, according to Baldwin & Schultes (1947), has 4 species and a variety distributed in the Amazon. However, Schultes (1952) considered them as synonyms of Micrandra, proposing thus new combinations. Webster (1994) drew attention to this fact, but kept Cunuria as a valid genus. The relationships between Micrandra, Cunuria, and Micrandropsis, the latter recently collected also in the state of Pará (it had been previously found only in the state of Amazonas), need to be better established.

According to Webster (1994), Dalechampia is a genus of Euphorbiaceae, subfamily Acalyphoideae, tribe Plukenetieae (Bentham) Hutchinson, positioned isolatedly in the subtribe Dalechampineae, and it is composed of 100 species, out of which 90 are distributed in tropical America. In the APG system (APG II 2009), this genus is included in Euphorbiaceae s.s. It has an uncommon morphological characteristic to Euphorbiaceae, which is the specialized inflorescence of the type bilabiate, bisexual pseudanthia, with two involucral bracts, usually colorful, with separate staminate and pistillate flowers. This type of pseudanthia is different from that found in Pera. Webster & Armbruster (1991) recognized six sections for the 90 Neotropical species of the genus: Dalechampia section Rhopalostylis Pax & Hoffmann, D. section Dioscoreifoliae Pax & Hoffmann, D. section Cremophyllum (Scheidweiler) Baillon, D. section Coriaceae Pax & Hoffmann, D. section Tiliifolae Webster & Armbruster, and D. section Dalechampia. According to the survey carried out in the herbaria MG and IAN, and based on Webster & Armbruster (1991), 17 species occur in the Brazilian Amazon; only Dalechampia section Coriaceae has probably no representatives in the region. Gillespie & Armbruster (1997) revised 18 species of Dalechampia for the Flora of the Guianas, providing only 4 illustrations, whereas Armbruster in Webster et al. (1999) revised briefly the 12 species of the Flora of the Venezuelan Guiana. In Brazil, the study by Rodrigues (2007) is the most up-to-date, and included four species of Distrito Federal.

The taxonomic treatment of Dalechampia by Webster & Armbruster (1991) is still the most up-to-date. These authors provided a detailed study on the morphology, described briefly the genus, sections and subsections, and two new species that they proposed. However they did not provide full descriptions and illustrations for other species of the genus and did not cite most collections examined, providing only the citation of the types. Therefore, Secco & Bigio (unpublished data) are revising and updating the species of Brazil, providing detailed keys, descriptions, and illustrations, since they were not yet subjected to complete taxonomic treatment.

Webster (1994) states that Amanoa belongs to Euphorbiaceae, subfamily Phyllanthoideae, tribe Amanoeae (Pax & Hoffamann) Webster, together with Pentabrachion Müll.Arg., a monotypic genus of western Africa. However, according to the APG system (APG III 2009), the taxon would be part of the family Phyllanthaceae.

Most of the 16 Amanoa species occur in the Neotropics (13); only three are endemic to Africa. The genus was never subjected to a complete revision; the most recent study is still the one carried out by Hayden (1990), which provided an identification key for the Neotropical species, described four new species, proposed a new name (A. sinuosa Hayden), and commented on A. guianensis Aublet, a type species and its varieties. The taxonomic treatment by Hayden (1990) needs update, especially because many samples available in the herbaria of the IAN, INPA, and MG were not analyzed and new collections were accomplished lately, making it necessary to make a new approach to the genus. Webster et al. (1999) updated only the species present in the Flora of the Venezuelan Guiana. Secco (2005) has made a treatment for two species for the Flora of the Ducke Reserve, Manaus, state of Amazonas, and Secco et al. (2010) provided an updated checklist of the species present in Brazil.

In the herbaria of MG and IAN, the most representative of eastern Amazon, there are many collections lacking updated identification of Amanoa; some contain only fruits or other not seen with entire reproductive parts, so new collections are needed. Besides, the complete material (with flowers and fruits) needs to be analyzed by a specialist, since many samples were identified by comparison, and not always by specialists. This hinders the recognition of some species with more restricted distribution in the Amazon, such as Amanoa glaucophylla Muell. Arg., A. gracilima W.J. Hayden, and Amanoaneglecta W.J. Hayden.

Gymnanthes Swartz does also need further studies. This genus has approximately 40 species, according to Webster (1994), and belongs to the subfamily Euphorbioideae, tribe Hippomaneae, subtribe Hippomaninae. According to the APG II system, the genus belongs to Euphorbiaceae s.s. and includes also Actinostemon Mart. ex Kl. Although the greatest specialists in Euphorbiaceae, such as Pax & K. Hoffman (1912), Baillon (1858) and Mueller (1866), have kept Gymnanthes and Actinostemon as separate genera, Webster & Huft (1988) and Webster (1994) synonymized Actinostemon with Gymnanthes, since the characters to separate it from Gymnanthes are not convincing from the taxonomic perspective. Despite that, Webster et al. (1999) considered Actinostemon as an independent genus, separated from Gymnanthes. Esser (1999), in a partial taxonomic treatment of the Hippomaneae of Malaysia, mentioned the inclusion of Actinostemon in Gymnanthes proposed by Webster (1994), but did not keep it as a synonym of Gymnanthes. Previously, authors such as Jablonski (1967, 1969) and Gillespie (1993) kept Actinostemon and Gymnanthes separated, though Jablonski (1967) stated that the distinction of the two genera based on the number of the stamens is very ambiguous. The taxonomic treatment proposed by Jablonski (1969) is still insufficient, as the author did not describe or illustrate all species, detailing more the two new species described (Actinostemon unciformis Jabl., of Bahia, and A. appendiculatus Jabl., of northeastern, including Pernambuco, and southeastern Brazil, including Espírito Santo and probably Rio de Janeiro). Webster (pers. comm.) stated that he was inclined to reconsider Actinostemon as an autonomous genus, though he had included it in Gymnanthes (Webster 1994). He admits that Actinostemon is very close to Gymnanthes, and most representatives of Hippomaneae (ex. Sebastiania Sprengel, Actinostemon) have not been well delimited morphologically.

Studies by Melo (2006), revising Sebastiania, included some species of this genus in Gymnanthes/Actinostemon. According to this author, only the species of Sebastiania section Sebastiania should be included in Sebastiania.

The problems exposed above led to a study on species of Gymnanthes (and Actinostemon), emphasizing those found in the Amazon, as a contribution to the taxonomic delimitation of the aforementioned taxa, since both Webster (1994) and Esser (1999) admit that the generic delimitation of the Neotropical representatives of Hippomaneae is still under dispute.

II. Euphorbiaceae in the Northeastern Region

Studies on Euphorbiaceae s.l. in northeastern Brazil focused mainly the floras of the states of Bahia and Pernambuco. The diversity of this family is still poorly known, though some relevant studies have been carried out, aiming at solving mainly problems in the tribes Euphorbieae, Hippomaneae, Hureae, and Crotoneae, particularly in the genus Croton. In this aspect, a pioneer study by Bezerra & Fernandes (1982) stands out, which comprises six Croton species, locally known as 'marmeleiros', emphasizing the presence of Croton sonderianus Muell.Arg. as the most abundant in the region.

Studies comprising the entire family were carried out by Cordeiro (1995) for the Flora of Pico das Almas, Chapada Diamantina, and Carneiro et al. (2002) for the Euphorbiaceae of "Inselbergs of Milagres" (state of Bahia). For the whole northeastern region, Cordeiro & Carneiro-Torres (2006) listed 211 species and 45 genera in the plant checklist of northeastern Brazil. A comprehensive study on the family Euphorbiaceae for reserves in the Caatinga of Pernambuco was carried out by Lucena (2009), who studied 54 species. A synopsis of this family, comprising 25 species and 11 genera of Serra de Itabaiana National Park (state of Sergipe), was published by Lucena et al. (2009). Lucena & Alves (2010) added 29 Euphorbiaceae taxa, with comments, to the list of this family in the northeastern region.

Taxonomic treatments for genera and tribes were also carried out for Chapada Diamantina, located within Bahia and Pernambuco. Carneiro-Torres et al. (2003b) studied the genus Phyllanthus (currently Phyllanthaceae) reporting 11 species, and Carneiro-Torres et al. (2002) studied the tribe Euphorbieae and recognized 16 species. Still regarding Phyllanthus, Silva & Sales (2007), based on Silva (2004), found 17 species in the state of Pernambuco and 11 species in the Caatinga biome (Silva & Sales 2004). A synopsis of Phyllanthus with 36 species for northeastern Brazil was also published by Silva & Sales (2008). Silva (2009) described two new species of Phyllanthus. The study of Cnidoscolus Pohl for the state of Pernambuco was carried out by Melo & Sales (2008). Santos & Sales (2009) studied also the tribe Hippomaneae in the state of Pernambuco.

Revision and morphological phylogeny studies were carried out and other are in developmental phase focusing mainly the genera of the tribe Hipomaneae. The revision of Sebastiania, currently circumscribed to 19 species, was developed by Melo (2006). Studies on morphological phylogeny of Sebastiania, including 17 species and 13 species of other Hippomaneae genera and the use of carpological characters in the delimitation of genera of the tribe Hippomaneae were developed by Souza (2011) and submitted for publication. Revisions and morphological and molecular phylogeny studies of Gymnanthes and Stillingia Garden ex L. are being carried out. For the tribe Hureae studies on morphological phylogeny and a synopsis of the species of this tribe have been carried out by Oliveira (2010), who analyzed 17 species of the genera Algernonia Baill. (11 species), Hura L. (1 species), and Ophthalmoblapton Allemão (4 species); Tetraplandra was considered as a subgenus of Algernonia.

The best studied Euphorbiaceae genus in northeastern Brazil is doubtless Croton, in particular in the semi-arid region. Local and regional floras and revisions of sections have been published. The revision of Croton section Argyroglossum in Brazil was carried out by Gomes (2006) and Gomes et al. (2010). A morphological phylogeny study on Croton section Ocalia is being concluded. Silva et al. (2009) studied 15 species of Croton of the micro-region of Vale do Ipanema, in the Caatinga biome, state of Pernambuco. In this state, Silva et al. (2010) published a synopsis of Croton, reporting 35 species of the genus. Attention should be given to Croton in the Caatinga biome, including the phytogeography of this genus, of which 68 species were recognized by Carneiro-Torres (2009). Lucena (2000) analyzed 14 species that occur in Zona do Litoral and Zona da Mata of Pernambuco. Still regarding Croton, a study on trichomes of species that occur in Pernambuco was carried out by Lucena & Sales (2006). Other studies are in the phase of data collection, standing out the studies of Croton in Chapada do Araripe, state of Ceará, and Vale do Catimbau National Park, Buique, state of Pernambuco, and the flora of the state of Rio Grande do Norte.

Recently, some new species have been described for northeastern Brazil. A new species of Gymnanthes was proposed by Esser et al. (2010). Gomes et al. (2010) described a new species of the genus Croton, and Carneiro-Torres et al. (2011) described three new species for this genus in the Caatinga.

Although Euphorbiaceae studies have advanced recently, there are still many groups that need to be studied. Among Hippomaneae, the genus Sapium P. Browne deserves attention for the difficulty of delimiting its species. The species of Croton that occur in forests and restingas still need to be further investigated.

III. Euphorbiaceae in the Southeastern Region

IIIa. Research in São Paulo

In the case of the research group of the state of São Paulo, the most recent studies focused mainly Euphorbiaceae s.s. and Phyllanthaceae, comprising revisions, floras, and descriptions of new species.

Floras: The survey carried out in Cadeia do Espinhaço by Lima (2001) and Lima & Pirani (2003) reported 22 species: Croton antisyphiliticus Mart., C. argyroglossum Baill., C. atrorufus Muell.Arg., C. buxifolius Muell.Arg., C. campestris A. St.-Hil., C. celtidifolius Baill., C. floribundus Spreng., C. glutinosus Muell.Arg., C. grewioides Baill., C. julopsidium Baill., C. lobatus L., C. lundianus Muell.Arg., C. migrans Casar., C. muscicarpa Muell. Arg., C. mysinites Baill., C. nummularius Baill., C. siderophyllus Baill., C. subferrugineus Muell.Arg., C. timandroides Muell.Arg., C. urucurana Baill., C. aff. desertorum Muell.Arg., and C. aff. petraeus Muell.Arg.

The study on the tribe Crotoneae in the state of São Paulo (Caruzo 2005; Caruzo & Cordeiro 2007) reported 37 Croton species and two Astraea Klotzsch species. Among the Croton species, several occur also in other countries, and some are broadly distributed all over the Neotropics, such as C. glandulosus L, C. hirtus L'Herit, C. pedicellatus Kunth, and C. triqueter Lam.; others are moderately distributed in South America: they occur in Bolivia, Paraguay, Argentina, Uruguay, and center-western, southeastern and southern Brazil, such as C. urucurana Baill., C. didrichsenii Webster, and C. rottlerifolius Baill.; in Argentina, Paraguay, and Brazil, such as C. antisyphiliticus Mart. ; in Bolivia, Paraguay, center-western, southeastern and southern Brazil, such as C. gracilipes Baill.; in Paraguay and most part of Brazil, such as C. floribundus Spreng. ; in Argentina, Uruguay, southeastern and southern Brazil, such as C. lanatus Lam.; in Bolivia, center-western, southeastern and southern Brazil, such as C. grandivelus Baill.; in Paraguay, center-western, southeastern and southern Brazil, such as C. serratifolius Baill.; in Argentina, southeastern and southern Brazil, such as C. glechomifolius Muell. Arg.; and in Bolivia, northeastern and southeastern Brazil, such as C. tricolor Klotzsch ex Baill. Among the species exclusively Brazilian are: C. lundianus (Didr.) Muell.Arg, which occurs all over Brazil; C. piptocalyx Muell. Arg., found in northeastern, center-western and southeastern Brazil; C. macrobothrys Baill., found in northeastern, southeastern and southern Brazil; C. fuscescens Spreng., C. hemiargyreus Muell.Arg. and C. sphaerogynus Baill., present in northeastern and southeastern regions; C. fuscus (Didr.) Muell.Arg., C. leptobotryus Müll.Arg., C. sancti-crucis S. Moore and C. sclerocalyx (Didr.) Muell.Arg., in center-western and southeastern; C. alchorneicarpus Croizat, C. ceanothifolius Baill. , C. celtidifolius Baill., C. dichrous Muell.Arg., C. heterodoxus Baill, C. organensis Baill. , C. salutaris Baill., C. serpyllifoius Baill. and C. vulnerarius Baill., in southeastern and southern; C. compressus Lam. and C. erythroxyloides Baill., with distribution restricted to southeastern Brazil; and C. priscus Croizat endemic to the state of São Paulo.

Besides, a Rapid Color Guide, containing photos of the tree Croton species of the Atlantic Forest, was produced and distributed by the Field Museum of Natural History (Caruzo 2005).

The Flora of Grão Mogol, state of Minas Gerais (Cordeiro 2004), reported 15 genera and 38 species of Euphorbiaceae s.l.: Acalypha L. (1), Alchornea (1), Bernardia Houstoun ex Miller (1), Chamaesyce S.F. Gray (2), Croton (11), Dalechampia (1), Euphorbia L. (2), Mabea (1), Manihot (1), Maprounea Aublet (1), Pera (1), Phyllanthus (5), Richeria (1), Sebastiania (7), and Stillingia (1).

Among ongoing flora studies are the one of the state of São Paulo, in which the family Euphorbiaceae s.s. is represented by 36 genera and ca. 139 species, as follows: Acalypha (14), Actinostemon (3), Adelia L. (1), Alchornea (3), Algernonia (1), Aparisthmium (1), Astraea (2), Bernardia (3), Caperonia A.St.-Hil. (3), Caryodendron Karsten (1), Chaetocarpus Thwaites (1), Chiropetalum A. Jussieu (2), Cnisdoscolus Pohl (2), Croton (37), Dalechampia (12), Euphorbia (17), Jatropha L. (2), Joannesia Vellozo (1), Mabea (2), Manihot (9), Microstachys A. Juss. (5), Maprounea (1), Margaritaria (1), Micrandra (1), Pachystroma Muell. Arg. (1), Pausandra Radlk. (1), Pera Mutis (2), Philyra Klotzsch (1), Plukenetia L. (1), Ricinus L. (1), Romanoa Trevisan (1), Sapium (2), Sebastiania (3), Tetraplandra Baillon (1), Tetrorchidium (1), and Tragia Plumier ex L. (6); and the Phyllanthaceae by 5 genera and 5 species: Gonatogyne Muell. Arg. (1), Hieronyma Fr. All. (1), Margaritaria (1), Richeria (1) and Savia McPherson (1). Among these genera, monographs on Croton and Astraea have already been prepared by Caruzo & Cordeiro (2007), whereas those on Dalechampia, Plukenetia, Romanoa, and Tragia are still in preparation (R. Secco, personal communication).

The monograph on the genus Phyllanthus (Phyllanthaceae), represented by 16 species in the state of São Paulo, has already been concluded (Martins & Lima 2011, in press).

Reviews: Among revisions of the genus is the study by Lima (2006) on Croton section Lamprocroton (Muell. Arg.) Pax. This section is entirely Neotropical, with an interesting disjoint distribution between South America and Mexico, and is characterized by the shrubby habit of its species, indumentum of lepidote trichomes, absence of cymules on the inflorescence, and bifid style branches (Lima & Pirani 2008). Twenty-six species were recognized in the section, among which three were new: C. imbricatus L.R. Lima & Pirani, C. muellerianus L.R. Lima & Pirani, and C. pygmaeus L.R. Lima & Pirani; the first endemic to the state of Bahia, the second to Paraná and the third endemic to Rio Grande do Sul. In addition to the taxonomic treatment and phylogenetic analysis of the section, morphological studies of leaf trichomes and pollen grains of some of its species have been also carried out.

Caruzo (2010) made another revision on Croton section Cleodora (Klotzsch) Baill. Caruzo et al. (2011) assessed the phylogenetic relationships of this section, using the nuclear region ITS and the plastidial regions trnL-F and trnH-psbA, separately and combined. In the individual phylogenies and in that with combined data, species of the section Cleodorasensu Webster (1993) emerged, almost in their totality, together with other species that had been originally not included in the section, forming a strongly supported clade characterized by two morphological synapomorphies: female flowers with imbricate sepals and style united at the base or above. Croton section Cleodora is an exclusively Neotropical section that has an interesting disjoint distribution among Central America, Amazon, and Atlantic Forest. Eighteen species were recognized for this section; three of which were new (Caruzo et al. 2008; Caruzo et al. 2010a,b). The section is composed of arboreous or shrubby species, usually latescent, covered by trichomes that are adpressed/star-shaped, star-shaped/lepidote, lepidote or more rarely star-shaped and multiradiate; the leaves exhibit a pair of acropetiolar or basilaminar glands; inflorescences are terminal, rarely axillary, basal cymules, usually bisexual; male flowers are campanulate, rarely subcampanulate, valvate or slightly imbricate, with stamens between 15-25; female flowers are campanulate to urceolate, in general conspicuously imbricate, styles 4-fidus or multifidus, united at the base or above, usually forming a crown. In this new circumscription of the section Cleodora, two new subsections were recognized: Sphaerogyni, characterized by sepals with quincuncial estivation in its pistillate flowers, and Spruceani, characterized by sepals with imbricate or reduplicate-valvate estivation.

The revison of Microstachys, associated with a phylogeny of Hippomaneae, is in progress (I. Cordeiro, personal communication).

Brasiliocroton P.E. Berry & Cordeiro, a new genus, and the reestablishment of Astraea: according to Berry et al. (2005a), the erect stamens on the flower bud of Brasiliocrotonmamoninha P.E. Berry & Cordeiro are the main morphological characteristic that differentiates it from Croton. However, the best justification for the establishment of this new genus is its position as sister-group of most Croton species, with the exception of Crotonlobatus L. and C. praetervisus Muell.Arg., which belong to Croton section Astraea (Klotzsch) Baill. In order to make Croton a monophyletic group, Berry et al. (2005b) incorporated into the taxon other small genera formally placed in the tribe Crotoneae and excluded from it species of the section Astraea, which was reestablished by the authors as the genus Astraea Klotzsch.

IIIb. Research in Rio de Janeiro

In the state of Rio de Janeiro, research has been focused on Euphorbiaceae s.l. Studies started in the 1970s with the taxonomic revision of the genera Algernonia Baill. and Tetraplandra Baill. Following these studies, Emmerich (1981) proposed new species (A. glaziouii and A. paulae) and a new combination: A. gibbosa (Pax & K. Hoffm.) Emmerich. Oliveira (1985) studied Sebastiania corniculata (Vahl) Müll.Arg. (currently a synonym of Microstachyscorniculata (Vahl) Griseb.).

In the 1980s, studies focused taxonomic problems at different infrageneric levels. The validity of infraspecific taxa, accepted at that time, was tested by several researchers. Senna-Valle (1983) showed that the infraspecific taxa of Pachystroma ilicifolium Müll. Arg. (currently Pachystromalongifolium (Nees) I.M.Johnst.) were no more than phenotypic expressions of characters, such as shape and leaf dimensions; these variations occur frequently in a single individual. These taxonomic studies were almost invariantly associated with anatomical and palynological studies, which observed the presence of structures that could be used in the taxonomic characterization of the Euphorbiaceae, such as the presence of Rosanoff's crystals in Actinostemon concolor (Spreng.) Muell. Arg. (Emmerich & Senna-Valle 1983). In the same genus, Senna-Valle (1983, 1984, 1985) studied A. communis var. spathulatus (Muell. Arg.) Pax (currently A.klotzschii (Didr.) Pax), A. verticillatus (Klotzsch) Baill., and A. concolor (Spreng) Muell. Arg. – all present in the state of Rio de Janeiro. Oliveira & Senna (1983) also studied leaf anatomy for the characterization of Anabaenella tamnoides (Juss.) Pax & Hoffm. In Sebastiania Spreng., Oliveira & Penna (1985) studied the taxa S. brasiliensis var. erythroxyloides (Muell.Arg.) Muell.Arg. (currently Sebastianiabrasiliensis Spreng.), and S. glandulosa var. fallax (Müll.Arg.) Pax (currently Microstachyscorniculata (Vahl) Griseb.), approaching their taxonomy and leaf anatomy. Palynological studies were associated with taxonomic studies on Sebatiania Spreng. (Gonçalves-Esteves et al. 1986). Oliveira & Sá-Haiad (1988) pointed out structural similarities and differences between Euphorbia heterophylla L. and E. cyathophora Murray. Emmerich (1987) devoted herself to the taxonomic study of Mabea fistulifera Mart. Oliveira et al. (1989) studied the Euphorbiaceae that occur in the restingas of the state of Rio de Janeiro from a floristic and taxonomic perspective.

In addition to those, stand out revisions of Chaetocarpus Sw. (Alves 1982) and taxonomic/floristic studies, such as those on Alchornea Sw. that occur in Rio de Janeiro (Silva 1993), Dalechampia Plum. (Maia et al. 2002), Pera glabrata (Penna 1981), and Croton L. (Sá-Haiad 1987). The latter was pioneering in Brazil regarding the use of scanning microscopy for studying Euphorbiaceae species. It is important to emphasize the multidisciplinary approach of these studies, in which leaf anatomy and pollen grains were used as subsidies for a better taxonomic revision of the species.

In the 1990s, studies focused the taxonomy of genera and species found in different Brazilian ecosystems, studying the morphology of taxa such as Croton urticifolius Lam., Sebastiania bidentata (Mart. & Zucc.) Pax (currently Microstachysbidentata (Mart. & Zucc.) Esser, following Oliveira & Ferraz (1991)), Caryodendrongrandifolium (Muell.Arg.) Pax (currently Caryodendronjaneirense Muell. Arg., following Senna-Valle & Campos (1992)), and nomenclatural types in the family (Oliveira & Senna 1991). Silva (1993) studied varieties of Alchornea triplinervia (Spreng.) Muell.Arg., and only two out of the eight previously established varieties were accepted. In regional studies, Euphorbiaceae was recorded in florulas, such as the Flora of Mato Grosso, mainly through studies on species of Sebastiania Spreng. and Sapium P. Br (Oliveira 1991); the Flora of the Cairuçu Reserve - Parati, Rio de Janeiro; the Flora of the Restinga de Jurubatiba National Park – Rio de Janeiro (Oliveira et al. 1997); and the Flora of the Atlantic Forest of southeastern Brazil. With a multidisciplinary approach, stand out the studies on the sexual system and pollination types of some Euphorbiaceae of sandy coastal plains (restinga) (Oliveira et al. 1989) and studies on Caperonia, Chamaesyce Gray, Croton L., Euphorbia, Sebastiania Spreng. and Stillingia Gard. Senna-Valle (1999) studied the complex Sapiumglandulatum (Vell.) Pax (currently Sapiumglandulosum (L.) Morong), assessing phytochemical, anatomic, palynological, pharmacological, and taxonomic aspects.

From the 2000s on, the number of monographs, dissertations, and theses that focused the family increased. Medeiros et al. (2002, 2007, 2009, 2011) devoted themselves to the taxonomic and morphological study of Croton species present in rocky fields of Minas Gerais. Initially, the study was restricted to the São José Mountain Range, Tiradentes, as part of the Flora of São José Mountain Range (Alves & Kolbek 2009). The species richness of Croton section Medea identified in this study led to the morphological and taxonomical study of the section, using specimens from southeastern Brazil. In these studies, the focus was the taxonomic validation of rare species, which were lacking in herborized collections. Some of these species were rediscovered (such as Croton gnidiaceus Baill., C. josephinus Muell.Arg. and C. staechadis Baill.), as they have been no longer collected since the type material was described. As a result from this approach and due to the high endemism in rocky fields, three new species were described for the section. The section could be recognized through a matrix of relevant morphological characters for its circumscription. Pinto (2004) studied the biological diversity of Euphorbiaceae in Serra da Tiririca State Park, Niterói, state of Rio de Janeiro, and recorded 21 genera and 41 species. Sá-Haiad et al. (2009) carried out studies aiming at contributing to the knowledge of relationships among Croton,Brasiliocroton, and Astraea. Morphological, anatomical, and palynological analyses were used to describe and compare species. The main objective of this study was to search for structural elements to be used in analyses of the lineage of crotonoids. Vegetative characteristics – both morphological and anatomical – as well as the presence of reduced petals on pistillate flowers – are similar among the studied specimens of Croton section Cyclostigma and Brasiliocroton mamoninha, differing from Astraea. The presence and protodermal origin of the idioblasts with lipophilic content and the interruption of the palisade by collenchyma layers on the adaxial side of the mid vein are common to the Croton L. species analysed and Brasiliocroton. The type of inflorescence, as well as some morphological characters of its reproductive structures, distinguishes B. mamoninha from the other two genera. The average size of the pollen grains of the studied species of Astraea and B. mamoninha differs from that of representatives of Croton section Cyclostigma, which have large pollen grains. The presence of dorsiventrality, paracytic stomata, collateral vascular bundles, branched non-articulated laticifers and crystal idioblasts as well as spheroidal, unaperturate and with a croton-type ornamentation pattern pollen grains in the species studied indicates morphological similarities among the three genera. The interpretation of the stipite of the complex trichomes as emergences is a structural novelty for the group. The presence of innumerable characteristics associated with defense mechanisms, such as trichomes, idioblasts with crystal and/or with lipophilic content, laticifers and extrafloral nectaries, especially in the genus Croton, together with the possibility of both anemophilous and entomophilous pollination, may represent one of the explanations for its great success, which is manifested by a pantropical distribution and by the large number of species (Sá-Haiad et al. 2009). This group of researchers contributed with the study on Peraceae for the list of Brazil (Bigio et al. 2010). Currently, the group is devoted to the study of species of Euphorbiaceae s.l. present in the Flora of the State of Rio de Janeiro.

IV. Euphorbiaceae in the Southern Region

In the southern region, studies with a more general approach stand out: Smith & Downs (1959) made a preliminary assessment of the Euphorbiaceae of Santa Catarina; Rambo (1960) presented a list of 15 genera and 64 species of Euphorbiaceae in the state of Rio Grande do Sul, based on data of a private herbarium owned by the author; Klein (1977) provided morphological and ecological data of 27 Croton species in the state of Santa Catarina; Allem (1978) made a preliminary taxonomic assessment of ca. 40 Croton species in Rio Grande do Sul.

Allem (1979) proposed four new species and a section (Calycireduplicatae Allem) of Croton for Rio Grande do Sul. According to this author, these species would be represented by dioecious plants, what would be something extraordinary, since the Croton species known so far are all monoecious, usually with pistillate flowers on the base and staminate flowers on the rest of the rachis. However, in his descriptions, Allem (1979) states that the staminate and pistillate flowers are in separate inflorescences, but on the same individuals, hence, those species would be, in fact, monoecious.

Probably, the greatest contribution to the taxonomic study of the Euphorbiaceae of southern Brazil was made by Smith et al. (1988), in a taxonomic treatment entitled Flora Ilustrada Catarinense. These authors used the old subdivision of the family, approaching the subfamilies Phyllanthoideae (with two ovules in each locule of the ovary), in which stood out genera such as Phyllanthus and Richeria, among others, and Crotonoideae (with one ovule in each locule of the ovary), in which most genera were placed, such as Acalypha, Croton, Euphorbia, etc.

It was proven that studies on Euphorbiaceae s.l are growing, particularly in the northern, northeastern, and southeastern regions of Brazil, with still some gaps in the central and southern regions. Research in these two last regions will lead to a broader knowledge of this important family.

There are many studies on Brazilian species of Croton L. However, species of the states of Mato Grosso, Goiás, part of the Brazilian Amazon (Pará, Amazonas, Amapá, and Roraima), Rio Grande do Sul, and Paraná, especially herbs, need revision.

There is a need for taxonomic revision/update also for Phyllanthus, Dalechampia, Drypetes, Mabea, and Sapium Jacq.; the latter is still a great challenge. In addition, we point out the need for more comprehensive taxonomic studies on the Brazilian Hippomaneae, in particular due to the changes in this taxon in the past few years, what lead to the establishment of novelties such as Pseudosenefeldera Esser, Dendrothrix Esser, Rhodothyrsus Esser, and Pleradenophora Esser.

We noticed a lack of published studies in Brazil on molecular systematics of the Euphorbiaceae s.s., Phyllanthaceae, Picrodendraceae, and Putranjivaceae. We believe that graduate programs can provide the means to form new taxonomists and to choose modern methods for the taxonomic treatment of the genera that need additional studies, in order to define the species better. Special attention should be given to Peraceae, since this group is still being debated.

Acknowledgements

Inês Cordeiro, Margareth Sales, and Ricardo Secco thank the Brazilian Research Council (CNPq) for the productivity fellowships granted for the study of Euphorbiaceae in the southeastern, northeastern, and northern regions of Brazil. The PhD Alessandro Rosário formatted the text.

Artigo recebido em 20/06/2011.

Aceito para publicação em 24/11/2011.

• Allem, A.C. 1978. Preliminares para uma abordagem taxonômica do gênero Croton L. (Euphorbiaceae) no Rio Grande do Sul. Boletim do Museu Botânico Municipal 34: 1-32.
• Allem, A.C. 1979. Quatro novas espécies de Croton L. (Euphorbiaceae) do Rio Grande do Sul. Boletin de la Sociedad Argentina de Botânica 18: 63-81.
• Alves, M. V. S. 1982. Chaetocarpus Tw. (Euphorbiaceae). Espécies do continente americano. Dissertação de Mestrado. Universidade Federal do Rio de Janeiro, Rio de Janeiro. 84p.
• Alves, R.J.V. & Kolbek, J. 2009. Summit vascular flora of Serra de São José, Minas Gerais, Brazil. Checklist 5: 35-73.
• APG II. 2003. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141: 399-436.
• APG III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society 161: 105-121.
• Baillon, H. 1858. Étude générale du groupe des Euphorbiacées. Victor Masson, Paris.
• Baldwin, J. & Schultes, R.E. 1947. A conspectus of the genus Cunuria Botanical Museum Leaflets of Harvard University 12: 325-351.
• Bentham, G. 1878. Notes on Euphorbiaceae. Journal of Linnean Society of London, Bot. 17: 185-267.
• Bentham, G. 1880. Euphorbiaceae. In: G. Bentham & J. D. Hooker, J (eds.). Genera Plantarum 3: 239-340.
• Berry, P.E.; Cordeiro, I.; Wiedenhoeft, A.C.; Vitorino-Cruz, M.A. & Lima, L.R. 2005a. Brasiliocroton, a new crotonoid genus of Euphorbiaceae from eastern Brazil. Systematic Botany 30: 356-364.
• Berry, P.E.; Hipp, A.L.; Wurdack, K.J.; Ee, B.V & Riina, R. 2005b. Molecular phylogenetics of the giant genus Croton and tribe Crotoneae (Euphorbiaceae s.s.) using ITS and trnL-trnF DNA sequence data. American Journal of Botany 92: 1520-1534.
• Bezerra, P. & Fernandes, F. 1982. Marmeleiros do Nordeste. Anais do XXXIII Congresso Nacional de Botânica. Pp. 145-156.
• Bigio, N.C. 2009. As espécies de Pera Mutis (Euphorbiaceae) na Amazônia brasileira. Dissertação de Mestrado. Universidade Federal Rural da Amazônia, Museu Paraense Emílio Goeldi, Belém. 117p.
• Bigio, N.C.; Secco, R.; Oliveira, A.S.; Senna-Valle, L.; Medeiros, D. & Pinto, L.J.S. Peraceae. 2010. In: Forzza, R.C. et al (org.). Catálogo de plantas e fungos do Brasil. Vol. 2. JBRJ, Rio de Janeiro. Pp. 1437-1438.
• Bigio, N.C. & Secco, R.S. 2010. Uma nova espécie de Pera (Peraceae), endêmica de Manaus, Amazonas, Brasil. Rodriguésia 61: 77-81.
• Bigio, N.C. & Secco, R.S. 2011. A new species of Pera (Euphorbiaceae) from Amazonian Brazil. Novon 21: 169-173.
• Bigio, N.C. & Secco, R.S. 2012. As espécies de Pera (Euphorbiaceae s.s) na Amazônia brasileira. Rodriguésia 63: neste volume.
• Carneiro, D.S.; Cordeiro, I. & França, F. 2002. A família Euphorbiaceae na flora de inselbergs da região de Milagres, Bahia, Brasil. Boletim de Botânica da Universidade de São Paulo 20: 31-47.
• Carneiro-Torres, D.S.; Santos, F.A.R. & Giulietti, A.M. 2002. A tribo Euphorbieae Dumort (Euphorbiaceae) na Chapada Diamantina, Bahia, Brasil: palinologia e implicações taxonômicas. Polibotánica 13: 83-96.
• Carneiro-Torres, D.S.; Giulietti, A.M. & Cordeiro. I. 2003a. A tribo Euphorbieae Dumort (Euphorbiaceae) na Chapada Diamantina, Bahia, Brasil. Acta Botanica Brasilica.
• Carneiro-Torres, D.S.; Cordeiro, I. & Giulietti, A.M. 2003b. O gênero Phyllanthus L. (Euphorbiaceae) na Chapada Diamantina, Bahia, Brasil. Acta Botanica Brasilica 17: 265-278.
• Carneiro-Torres, D.S. 2009. Diversidade de Croton L. (Euphorbiaceae) no bioma Caatinga. Tese Doutorado. Universidade Estadual de Feira de Santana, Feira de Santana.
• Carneiro-Torres, D.S.; Cordeiro, I. ; Giulietti, A.M.; Berry, P.E. & Riina, R. 2011. Three new species of Croton (Euphorbiaceae s.s) from the Brazilian Caatinga. Brittonia 63: 122-132.
• Carreira, L.M.M.; Secco, R.S. & Barth, O.M. 1996. Pólen morphology of lianescent species of the genus Croton (Euphorbiaceae). Grana 35: 74-78.
• Caruzo, M.B.R. 2005. Estudo taxonômico e biogeográfico do gênero Croton L. (Euphorbiaceae) no estado de São Paulo, Brasil. Dissertação de Mestrado. Universidade de São Paulo. São Paulo.
• Caruzo, M.B.R. & Cordeiro, I. 2007. Sinopse da tribo Crotoneae Dumort. (Euphorbiaceae s.s) no estado de São Paulo, Brasil. Hoehnea 34: 571-585.
• Caruzo, M.B.R.; Riina, R.; Cordeiro, I. & Berry, P.E. 2008. Croton campanulatus (Euphorbiaceae s.s.), a new species from the Brazilian Atlantic rain forest. Brittonia 60: 261-264.
• Caruzo, M.B.R. 2010. Sistemática de Croton sect. Cleodora (Euphorbiaceae s.s.). Tese de Doutorado. Universidade de São Paulo.
• Caruzo, M.B.R.; Cordeiro, I.; Berry, P. & Riina, R. 2010a. A new species of Croton section Cleodora (Euphorbiaceae s.s) from Minas Gerais, Brazil. Phytotaxa 3: 27-33.
• Caruzo, M.B.R.; Riina, R.; Cordeiro, I. & Berry, P.E. 2010b. Crotonrufolepidotus (Euphorbiaceae s. str.), a New Species from Antioquia, Colombia. Novon 20: 248-251.
• Caruzo, M.B.R.; Van Ee, B.; Cordeiro, I.; Berry, P.E. & Riina, R. 2011. Molecular phylogenetics and character evolution of the "sacaca" clade: novel relationships of Croton section Cleodora (Euphorbiaceae). Molecular Phylogenetics and Evolution 60: 193-206.
• Cordeiro, I. 1995. Euphorbiaceae. In: Stannard, B.L. (ed.). Flora do Pico das Almas, Chapada Diamantina, Bahia-Brasil. Royal Botanic Gardens, Kew. Pp. 300-317.
• Cordeiro, I. 2004. Flora de Grão-Mogol, Minas Gerais: Euphorbiaceae. Boletim de Botânica da Universidade de São Paulo 22: 109-131.
• Cordeiro, I. & Carneiro-Torres, D.S. Euphorbiaceae. 2006. In: Barbosa, M.R.V.; Sothers, C.; Mayo, S.; Gamarra-Rojas, C.F.L.; Mesquita, A.C. (orgs.). Checklist das plantas do nordeste brasileiro: angiospermas e gimnospermas. Ministério de Ciência e Tecnologia, Brasília. 157p.
• Cordeiro, I.; Secco, R.S; Carneiro-Torres, D.S.; Lima, L.R.; Caruzo, M.B.R.; Berry, P.E. & Riina, R.G. 2010. Croton.In: Lista de espécies da flora do Brasil. Jardim Botânico do Rio de Janeiro. Available in <http://floradobrasil.jbrj.gov.br/2010/FB022689>. Access on Jun 2011.
• Cronquist, A. 1981. An integrated system of classification of flowering plants. Columbia University Press, New York.
• Emmerich, M. 1981. Revisão taxonômica dos gêneros Algernonia Baill. E Tetraplandra Baill. (Euphorbiaceae-Hippomaneae). Arquivos do Museu Nacional 56: 91- 110.
• Emmerich, M. & Senna-Valle, L. 1983. Cristais de Rosanoff. - Estruturas presentes em Actinostemon concolor (Spreng) Mull. Arg. (Euphorbiaceae). Bradea 3: 433-436.
• Emmerich, M. 1987. Nova conceituação de Mabea fistulifera Mart. (Euphorbiaceae). Bradea 47: 370-376.
• Engler, A. 1964. Syllabus de pflanzenfamilien-angiospermenn. Gebruder Borntraeger, Berlim. 666p.
• Esser, H-J. 1999. A partial revision of the Hippomaneae (Euphorbiaceae) in Malesia. Blumea 44: 149-215.
• Esser, H.J.; Lucena, M.F.A. & Alves, M. 2010. A new species of Gymnanthes (Euphorbiaceae) from northeastern Brazil. Willdenowia 40: 345-349.
• Gillespie, L. J. 1993. Euphorbiaceae of the Guianas: annotated species checklist and key to the genera. Brittonia 45: 56-94.
• Gillespie, L.J. & Ambruster, W.S. 1997. A contribution to the Guianan flora: Dalechampia, Haematostemon, Omphalea, Pera, Plukenetia and Tragia (Euphorbiaceae) with notes on subfamily Acalyphoideae. Smithsonian Contributions to Botany 86: 1-48.
• Gomes, A.P.S. 2006. Revisão das espécies sul-americanas de Croton L. subgen. Croton Sect. Argyroglossum Baill. (Crotonoideae-Euphorbiaceae). Tese de Doutorado. Universidade Federal Rural de Pernambuco.
• Gomes, A.P.S.; Sales, M. F. & Berry, P.E. 2010. Croton limae (Euphorbiaceae), a new species of section Argyroglossum from Brazil. Brittonia 62: 206-209.
• Gonçalves-Esteves, V.; Esteves, R.L. & Oliveira, A.S. 1986. Sebastiania Spreng. (Euphorbiaceae) - Estudo polínico das espécies ocorrentes no estado do Rio de Janeiro, Brasil. Boletim do Museu Nacional, Botânica 73: 1-11.
• Guimarães, L.A.C. & Secco, R.S. 2009. As espécies de Croton sect. Cyclostigma e Croton sect. Luntia subsect. Matourense (Euphorbiaceae s.s) ocorrentes na Amazônia brasileira. Acta Amazonica 40: 471-488.
• Hayden, W.J. 1990. Notes on neotropical Amanoa (Euphorbiaceae). Brittonia 42: 260-270.
• Hutchinson, J. 1969. Tribalism in the family Euphorbiaceae. American Journal of Botany 56: 738-758.
• Jablonski, E. 1967. Euphorbiaceae. In: Maguire, B. et al. (eds.). Botany of the Guayana Highland - part VII. Memories of the New York Botanical Garden 17: 80-190.
• Jablonski. E. 1969. Monograph of the genus Actinostemon Phytologia 18: 213-240.
• Judd, W. S.; Campbell, C. S.; Kellogg, E. A.; Stevens, P. F. & Donoghue, M. J. 2009. Sistemática vegetal: um enfoque filogenético. 3Ş ed. Artmed, Porto Alegre. 612p.
• Jussieu, A. 1824. Euphorbiaceae Generibus Medicisque earumdem viribus tentamen, tabulis aeneis 18 illustratum. Typis Didot Jurioris, Paris. Pp. 42-45.
• Klein, R.M. 1977. Dados morfológicos e ecológicos das espécies do gênero Croton do estado de Santa Catarina e sua dispersão geográfica. Anais do XXVI Congresso Nacional de Botânica. Academia Brasileira de Ciências, Rio de Janeiro. Pp. 289-305.
• Leal, C. 1951. Contribuição ao estudo da família Euphorbiaceae. Arquivos do Jardim Botânico do Rio de Janeiro 12: 63-79.
• Lima, L.R. 2001. O gênero Croton L. (Euphorbiaceae) na Cadeia do Espinhaço, Minas Gerais Brasil. Dissertação de Mestrado. Universidade de São Paulo, São Paulo.
• Lima, L.R. & Pirani, J.R. 2003. O gênero Croton L. na Cadeia do Espinhaço, Minas Gerais, Brasil. Boletim de Botânica da Universidade de São Paulo 21: 299-344.
• Lima, L.R. 2006. Revisão taxonômica e filogenia de Croton seção Lamprocroton (Müll.Arg.) Pax e estudo filogenético das seções sul-americanas do gênero Croton L. (Euphorbiaceae). Tese de doutorado. Instituto de Biociências, Universidade de São Paulo.
• Lima, L.R. & Pirani, J.R. 2008. Revisão taxonômica de Croton sect. Lamprocroton (Müll.Arg.) Pax (Euphorbiaceae s.s.). Biota Neotropica 8: 21-75.
• Lucena, M. F. A. 2000. Estudos taxonômicos do gênero Croton L. (Crotonoideae Euphorbiaceae) nas zonas do litoral e da Mata do estado de Pernambuco Brasil. Dissertação de Mestrado. Universidade Federal Rural de Pernambuco, Recife. 136p.
• Lucena, M. F. A. & Sales, M. F. 2006. Tricomas foliares em espécies de Croton L.. Rodriguésia. 57: 11-25.
• Lucena, M.F.A. 2009. Diversidade de Euphorbiaceae s.l. no Nordeste do Brasil. Tese de Doutorado. Universidade Federal de Pernambuco, Recife.
• Lucena, M.F.A.; Amorim, B.S. & Alves, M. 2009. Sinopse das espécies de Euphorbiaceae s.l. do Parque Nacional Serra de Itabaiana, Sergipe, Brasil. Revista Caatinga 22: 214-224.
• Lucena, M. F. A. & Alves, M. 2010. Notas taxonômicas para Euphorbiaceae s.l. do Nordeste do Brasil. Hoehnea 37: 71-85.
• Maia, V.C.R.; Emmerich, M. & Senna-Valle, L. 2002. Dalechampia L. (Euphorbiaceae) - Taxonomia das espécies ocorrentes no estado do Rio de Janeiro, Brasil. Boletim do Museu Nacional, Rio de Janeiro.
• Martins, E.R. & Lima, L.R. 2011. Sinopse do gênero Phyllanthus L. (Phyllanthaceae) do estado de São Paulo. Hoehnea (no prelo).
• Medeiros, D. 2002. Euphorbiaceae Juss. da Serra de São José, Tiradentes, Minas Gerais, Brasil. Dissertação de Mestrado. Universidade Federal do Rio de Janeiro, Rio de Janeiro.
• Medeiros, D. 2007. Croton sect Medea (Klotzsch) Baill. no Sudeste do Brasil. Tese de Doutorado. Universidade Federal do Rio de Janeiro, Rio de Janeiro.
• Medeiros, D.; Senna-Valle, L. & Alves, R.J.V. 2002. Espécie nova de Croton L. (Euphorbiaceae) do estado de Minas Gerais, Brasil. Bradea 8: 299-302.
• Medeiros, D., Senna-Valle, L. & Alves, R. J. V. 2007. Euphorbiaceae nativas de cerrado e campo rupestre da Serra de São José, Minas Gerais, Brasil. Arquivos do Museu Nacional 66: 323-349.
• Medeiros, D.; Senna-Valle, L. & Alves, R.J.V. 2009. Two new species of Croton L. (Euphorbiaceae) from campos rupestres of Minas Gerais State, Brazil. The Journal of the Torrey Botanical Society 136: 186-191.
• Medeiros, D.; Senna-Valle, L. & Alves, R.J.V. 2011. Rediscovery of Croton josephinus (Euphorbiaceae) in Minas Gerais, Brazil. Edinburgh Journal of Botany 68: 33-38.
• Melo, A.L. 2006. Revisão de Sebastiania Spreng. (Euphorbiaceae-Hippomaneae). Tese de Doutorado. Universidade Federal Rural de Pernambuco, Recife.
• Melo, A.L. & Sales, M.F. 2008. O gênero Cnidoscolus Pohl (Crotonoideae-Euphorbiaceae) no estado de Pernambuco, Brasil. Acta Botanica Brasilica 22: 806-827.
• Mueller, J. (Müll.Arg.). 1866. Euphorbiaceae-Acalypheae. DC. Prodromus 15: 895-913.
• Mueller, J. 1873. Euphorbiaceae. In: Martius, C.F.P. & Eichler, A.G. (eds.). Flora brasiliensis 11: 1-292, tab. 1-42.
• Oliveira, A.S. & Senna, L.M. 1983. Anabaenella tamnoides (Juss. )Pax & Hoffm. (Euphorbiaceae Juss.) taxonomia e anatomia foliar. Acta da Sociedade Botânica do Brasil 1: 97-98.
• Oliveira, A.S. 1985. Sebastiania corniculata var. glabrata (Mart.) Mull. Arg. Considerações taxonômicas, ecológicas e de anatomia foliar. Revista Brasielira de Biologia 35: 87-100.
• Oliveira, A.S.& Penna, E.M. 1985. Sebastiania Spreng. (Euphorbiaceae) taxonomia e anatomia foliar III Sebastianiabrasiliensis var. erytroxyloides (Müll.Arg.) Müll.Arg. In: Atas da Sociedade Botânica do Brasil, Secção Rio de Janeiro 3: 25-32.
• Oliveira, A.S. 1988. Taxonomia das espécies do gênero Sebastiania sec. Elachocroton (Baill.) Pax (Euphorbiaceae) ocorrentes no Brasil. Arquivos Jardim Botânico 27: 1-89.
• Oliveira, A.S. & Sá-Haiad, B. 1988. Estudos taxonômicos sobre a família Euphorbiaceae Juss.- I: Euphorbia heterophylla L. e Euphorbiacyathophora Murr. Sellowia 40: 5-31.
• Oliveira, A.S.; Silva, I.M. & Alves, M.V.S. 1988. Estudos taxonômicos sobre a família Euphorbiaceae II - Alchornea triplinervia (Spreng.) Mull. Arg. var. triplinervia e Alchornea triplinervia var. janeirensis (Casar.) Mull. Arg. Sellowia 40: 32-62.
• Oliveira, A. S. & Senna-Valle, L. 1989. Euphorbiaceae Juss. Espécies ocorrentes nas restingas do estado do Rio de Janeiro. Acta Botanica Brasilica 3: 131-139.
• Oliveira, A.S.; Senna-Valle, L. & Alves, M.V. 1989. Estudos taxonômicos sobre a família Euphorbiaceae Juss. III- Croton urticaefolius Lam. Sellowia 4: 17-38.
• Oliveira, A.S. 1991. Sebastiania Spreng. (Euphorbiaceae) Taxonomia das espécies ocorrentes em Mato Grosso, Brasil. Boletim do Museu Nacional, Botânica 85: 1-16. 1991.
• Oliveira, A.S. & Ferraz, C.L.A. 1991. Sebastiania Spreng. (Euphorbiaceae) - S. bidentata (Mart.) Pax & Hoffm. Estudos taxonômicos e de anatomia foliar. Bradea 45: 412-423.
• Oliveira, A.S. & Senna, L.M. Euphorbiaceae Juss. In: Carvalho, L.D'A. et al. (orgs.). 1991. Tipus nomenclaturais caracterizados do herbário do Jardim Botânico do Rio de Janeiro. Série Estudos e Contribuições 3: 34-40.
• Oliveira, A.S.; Senna-Valle, L. & Emmerich, M. 1997. Flórula da APA Cairuçu, Parati, RJ. Espécies vasculares. Euphorbiaceae. Série Estudos e Contribuições Rio de Janeiro 14: 167-193.
• Oliveira, A.S.; Senna-Valle, L. & Emmerich, M. 1997. Mapeamento da cobertura vegetal e listagem das espécies ocorrentes na área de proteção ambiental de Cairuçu, Município de Parati, RJ. Série Estudos e Contribuições Rio de Janeiro 13: 62-63.
• Oliveira, A.S. 2001. Euphorbiaceae Juss. In: Costa, A.F. & Dias, I. A.C. (orgs.). Flora do Parque Nacional da Restinga de Jurubatiba e arredores. Brasil: listagem florística e fiteogreografia. MN/UFRJ, Série Livro 8: 69-73.
• Oliveira, L.S.D. 2010. Considerações filogenéticas e taxonômicas na tribo Hureae Dumort. (Euphorbioideae - Euphorbiaceae). Dissertação de Mestrado. Universidade Federal Rural de Pernambuco.
• Pax, F. & Hoffmann, K. 1912. Euphorbiaceae-Hippomaneae. In: Engler, A. (ed.). Das Pflanzenreich IV.147.v (Heft 52). Engelmann, Leipzig.
• Pax, F. & Hoffmann, K. 1914. Euphorbiaceae-Acalypheae-Mercurialinae. In: Engler, A. (ed.). Das Pflanzenreich IV. 147. VII: 7-259.
• Pax, F. & Hoffmann, K. 1919. Euphorbiaceae-Pereae. In: Engler, A. (ed.). Das Pflanzenreich IV.147.XIII (Heft 68): 1-14.
• Pax, F. & Hoffmann, K. 1931. Euphorbiaceae. In: Engler, A. & Prantl, K. (eds.). Die Nat. Pflanzenfamilien, Band 19c: 11-233.
• Penna, E.M. 1981. Estudos taxonômicos e morfológicos de Peraglabrata (Schott) Baill. (Euphorbiaceae). Dissertação de Mestrado. Universidade Federal do Rio de Janeiro, Rio de Janeiro. 84p.
• Pinto, L.J.S. 2004. A Família Euphorbiaceae A. Jussieu no Parque Estadual da Serra da Tiririca e arredores, Niterói RJ. Dissertação de Mestrado. Universidade Federal do Rio de Janeiro, Rio de Janeiro. 186p.
• Pires, J.M; Secco, R.S. & Ivanir, J.G. 2002. Taxonomia e fitogeografia das seringueiras (Hevea spp., Euphorbiaceae). Embrapa Amazônia Oriental, Belém. 103p.
• Radcliffe-Smith, A. 2001. Genera Euphorbiacearum Royal Botanic Gardens, Kew. 464p.
• Rambo, B. 1960. Euphorbiaceae Riograndenses. Pesquisa Botânica 9: 1-78.
• Reveal, J.L. & Chase, M.W. 2011. APGIII: Bibliographical Information and Synonymy of Magnoliidae. Phytotaxa 19: 71-134
• Rodrigues, A.S. 2007. As tribos Dalechampieae Müll.Arg. e Manihoteae Melchior (Euphorbiaceae) no Distrito Federal. Dissertação de Mestrado. Universidade de Brasília, Brasília.
• Sá-Haiad, B. 1987. Taxonomia e morfologia das espécies do gênero Croton sec. Croton subsec. Lasiogyne (Kl.) Muell. Arg, ocorrentes nas restingas do estado do Rio de Janeiro. Dissertação de Mestrado. Universidade Federal do Rio de Janeiro, Rio de Janeiro.
• Sá-Haiad, B.; Serpa-Ribeiro, A.C.C.; Barbosa, C.N.; Pizzini, D.; Leal, D.O.; Senna-Valle, L. & Santiago-Fernandes, L.D.R. 2009. Leaf structure of species from three closely related genera from tribe Crotoneae Dumort. (Euphorbiaceae s.s, Malpighiales). Plant Systematics and Evolution 283: 179-202.
• Santos, V.J. & Sales, M.F. 2009. A tribo Hippomaneae A. Juss. ex Spach. (Euphorbiaceae Juss.) no estado de Pernambuco, Brasil. Acta Botanica Brasilica 23: 976-990.
• Schultes, R.E. 1952. Studies in the genus Micrandra I: The relantionships of the genus Cunuria to Micrandra Botanical Museum Leaflets of Harvard University 15: 201-222.
• Schultes, R.E. 1979. Studies in the genus Micrandra II. Miscellaneous taxonomic and economic notes. Botanical Museum Leaflets of Harvard University. 27: 93-111.
• Schultes, R.E. 1987. Members of Euphorbiaceae in primitive and advanced societies. Botanical Journal of Linnean Society 94: 79-95.
• Secco, R.S. 1985. Notas sobre o novo conceito de Sagotia racemosa Baill. (Euphorbiaceae) em relação às suas variedades. Acta Amazonica (supl) 15: 81-85.
• Secco, R.S. 1987. Aspectos sistemáticos e evolutivos do genro Sandwithia Lanj. (Euphorbiaceae) em relação às suas afinidades. Boletim do Museu Paraense Emilio Goeldi, Botânica 3: 157-181.
• Secco, R.S. 1988. Dialissepalia no gênero Sandwithia Lanj. (Euphorbiaceae): uma novidade botânica do Alto Rio Negro e da Venezuela. Boletim do Museu Paraense Emilio Goeldi, série Botânica 4: 177-185.
• Secco, R. S. 1990a. Revisão dos gêneros Anomalocalyx, Dodecastigma, Pausandra, Pogonophora e Sagotia para a América do Sul. Coleção Adolpho Ducke. Museu Paraense Emílio Goeldi, Belém. 133p.
• Secco, R.S. 1990b. Padrões de distribuição geográfica e relações taxonômicas de algumas Crotonoideae (Euphorbiaceae) da Amazônia. Acta Botanica Brasilica 4: 91-103.
• Secco, R.S. 1993a. Notas sobre as lianas do gênero Croton (Euphorbiaceae). Boletim do Museu Paraense Emílio Goeldi 8: 265-281.
• Secco, R.S. 1993b. Alchornea fluviatilis: uma nova Euphorbiaceae da Amazônia brasileira. Boletim do Museu Paraense Emilio Goeldi, Botânica 9: 59-65.
• Secco, R.S. 1997. Notas adicionais sobre a taxonomia, morfologia e distribuição geográfica do gênero Nealchornea Huber (Euphorbiaceae). Revista Brasileira de Biologia 57: 61-69.
• Secco, R.S. 2001. Notas adicionais sobre a taxonomia e distribuição geográfica dos gêneros Alchorneopsis, Cleidion e Polyandra (Euphorbiaceae). Acta Botânica Brasilica 15:45-56.
• Secco, R.S. 2003. Contribuição adicional à taxonomia de Adenophaedra e Tetrorchidium (Euphorbiaceae). Acta Amazonica 33: 221-236.
• Secco, R.S. 2004a. Alchorneae (Alchornea, Aparisthmium e Conceveiba). Flora Neotropica. Vol. 93. The New York Botanical Garden Press, New York. Pp. 1-195.
• Secco, R.S. 2004b. Croton dissectistipulatus, a new species of Euphorbiaceae from Amazonian Brazil. Brittonia 56: 353-356.
• Secco, R.S. 2005. Flora da Reserva Ducke, Amazonas, Brasil. Euphorbiaceae- Parte I. Rodriguésia 56: 143-168.
• Secco, R.S. 2008a. A botânica da seringueira (Hevea brasiliensis (Willd. Ex Adr. Jussieu) Müll.Arg.). In: Alvarenga, A.P. & Carmo, C.A.F.S. (eds.). Seringueira. EPAMIG, Viçosa. 894p.
• Secco, R.S. 2008b. Sinopse das espécies de Croton L. (Euphorbiaceae) na Amazônia brasileira: um ensaio taxonômico. Coleção Adolpho Ducke. Museu Paraense Emílio Goeldi, Belém. 169p.
• Secco, R.S. & Cordeiro, I. 1999. Euphorbiaceae. In: Ribeiro, J.E.L.S. et al. (eds.). Flora da Reserva Ducke. INPA/DFID, Manaus. 816p.
• Secco, R.; Cordeiro, I. & Martins, E.R. 2010. PhyllanthaceaeIn: Forzza, R.C. et al. (orgs.). Lista de espécies da flora do Brasil. Jardim Botânico do Rio de Janeiro. Available in <http://floradobrasil.jbrj.gov.br/2010/FB038579>. Access on Jun 2011.
• Secco, R.S.; Esser, H.J.; Berry, P.E.; Riina, R. & Levin, G. 2008. Euphorbiaceae. In: Daly, D.C. & Silveira, M. (eds.). First catalogue of the flora of Acre. EDUFAC, Rio Branco. 555p.
• Secco, R.S. & Giulietti, A. M. 2007. Notas sobre a fenologia de Conceveiba guianensis Aublet (Euphorbiaceae) na Reserva Mocambo, Belém, PA. In: Almeida, S.S.; Martins, M.B.; Gomes, J.I. (org.). Mocambo: diversidade e dinâmica biológica da Área de Pesquisa Ecológica do Guamá (APEG). Museu Paraense Emilio Goeldi/Embrapa Amazônia Oriental, Belém. Pp. 309-316.
• Secco, R.S. & Rosário, A.S. 2009. Euphorbiaceae. In: Giulietti, A.M. et al. (orgs.). Plantas raras do Brasil. Conservação Internacional, Belo Horizonte. 496p.
• Secco, R.S. & Webster, G.L. 1990. Materiais para a flora amazônica. IX. Ensaio sobre a sistemática do gênero Richeria (Euphorbiaceae). Boletim do Museu Paraense Emílio Goeldi, série Botânica 6: 141-158.
• Senna-Valle, L. 1983. Actinostemon Kl. (Euphorbiaceae) Morfologia e taxonomia I - A. communis var. spathulatus Mull.Arg. Atas da Sociedade Botânica do Brasil Secção Rio de Janeiro 1: 87-96.
• Senna-Valle, L. 1983. Pachystroma longifolium (Nees) Johnston (Euphorbiaceae) - Espécie com interessante diversidade nas folhas. Bradea 3: 421-432.
• Senna-Valle, L. 1984a. Maprounea Aubl. (Euphorbiaceae) Considerações taxonômicas e anatômicas das espécies sul-americanas. Rodriguésia 36: 51-78.
• Senna-Valle, L. 1984b. Actinostemon Kl. (Euphorbiaceae) Aspectos morfológicos, anatômicos e taxonômicos II - Actinostemon verticillatus (Kl.) Baill. Bradea 4: 95-106.
• Senna-Valle, L. 1985. Actinostemon Kl. (Euphorbiaceae) Aspectos morfológicos e taxonômicos III - Actinostemon concolor (Spreng) Muell.Arg. Atas da Sociedade Botânica do Brasil Sec. Rio de Janeiro 3: 33-44.
• Senna-Valle, L. 1989. Espécies de Sapium Jacq. (Euphorbiaceae) que ocorrem no estado do Mato Grosso. Bradea 5: 196-204.
• Senna-Valle, L. & Campos, D.L. 1992. Caryodendron grandifolium (Muell.Arg.) Pax (Euphorbiaceae). Aspectos morfológicos e taxonômicos. Boletim do Museu de Biologia Mello Leitão 1: 61-64.
• Senna-Valle, L. 1999. Caracterização do "Complexo Sapium glandulatum (Vell.) Pax" (Euphorbiaceae). Tese de Doutorado. Universidade Federal do Rio de Janeiro, Rio de Janeiro. 148p.
• Silva, I.M. 1993. Alchornea Sw. Secção Alchornea (Euphorbiaceae) Espécies ocorrentes no estado do Rio de Janeiro. Dissertação de Mestrado. Universidade Federal do Rio de Janeiro, Rio de Janeiro. 120p.
• Silva, J.S. 2009. O gênero Croton L. (Euphorbiaceae) em Pernambuco, com ênfase nas espécies da microrregião do Vale do Ipanema. Dissertação de Mestrado. Universidade Federal Rural de Pernambuco.
• Silva, J.S.; Sales, M.F. & Carneiro-Torres, D.S. 2009. O gênero Croton L. (Euphorbiaceae) na microrregião do Vale do Ipanema, Pernambuco, Brasil. Rodriguésia 60: 879-901.
• Silva, J.S.; Sales, M. F.; Gomes, A. P. S. & Carneiro-Torres, D. S. 2010. Sinopse das espécies de Croton L. (Euphorbiaceae) no estado de Pernambuco, Brasil. Acta Botanica Brasilica 24: 441-453.
• Silva, M. J. 2004. O gênero Phyllanthus L. (Phyllanthaceae Martynov) no Nordeste do Brasil, com ênfase nas espécies de Pernambuco. Dissertação de Mestrado. Universidade Federal Rural de Pernambuco.
• Silva, M.J. & Sales, M.F. 2004. O gênero Phyllanthus L. (Phyllantheae Euphorbiaceae Juss.) no bioma Caatinga do estado de Pernambuco Brasil. Rodriguésia 55: 101-126.
• Silva, M.J. & Sales, M.F. 2007. Phyllanthus L. (Phyllanthaceae) em Pernambuco, Brasil. Acta Botanica Brasilica 21: 79-98.
• Silva, M.J. & Sales, M.F. 2008. Sinopse do gênero Phyllanthus (Phyllanthaceae) no Nordeste do Brasil. Rodriguésia 59: 407-422.
• Silva, M.J. 2009. Two new Brazilian species of Phyllanthus (Phyllanthaceae). Novon 19: 229-233.
• Smith, L.B. & Downs, R.J. 1959. Resumo preliminar das Euforbiáceas de Santa Catarina. Sellowia 11: 155-231.
• Smith, L.B; Downs, R.J. & Klein, R. 1988. Euforbiáceas. In: Reiz, R. (ed.). Flora ilustrada catarinense. Itajaí
• Souza, S.M.A. 2011. Estudos morfológicos e filogenéticos de Sebastiania Spreng. (Hippomaneae - Euphorbiaceae). Dissertação de Mestrado. Universidade Federal Rural de Pernambuco.
• Souza, V.C. & Lorenzi, H. 2008 Botânica sistemática: guia ilustrado para identificação das famílias de Angiospermas da flora brasileira, baseado no APG II. Instituto Plantarum, Nova Odessa. 640p.
• Stevens, P. F. 2001, and onwards. Angiosperm phylogeny Website. Version 9, June 2008. Available in <http://www.mobot.org/MOBOT/research/APweb/> Access on 15 Oct 2008.
• Trindade, M.J.S. & Secco, R.S. 2009. As Euphorbiaceae da FLONA de Caxiuanã com ênfase nas espécies da grade do PPBio. In: Lisboa, P.L.B. (org.). Caxiuanã: o desfaio para a conservação de uma floresta nacional na Amazônia. Belém. 672 p.
• Webster, G.L. 1975. Conspectus of a new classification of the Euphorbiaceae. Taxon 24: 593-601.
• Webster, G. L. 1987. The saga of the spurges: A review of classification and relationships of the Euphorbiales. Botanical Journal of the Linnean Society 94: 3-46.
• Webster, G. L. 1993. Provisional synopsis of the section of the genus Croton (Euphorbiaceae). Taxon 42: 793-823.
• Webster, G.L. 1994. Synopsis of the genera and suprageneric taxa of Euphorbiaceae. Annals of Missouri Botanical Garden 81: 33-144.
• Webster, G.L. & Armbruster, W.S. 1991. A synopsis of the neotropical species of Dalechampia (Euphorbiceae). Botanical Journal of the Linnean Society 105: 137-177.
• Webster, G.L.; Berry, P.E.; Levin, G.A.; Esser, H.J.; Hayden, J.; Armbruster, W.S.; Secco, R.S. & Heald, S. 1999. Euphorbiaceae. In: Steyermark, J.A.; Berry, P.E.; Yatskievych, K.; Holst, B.K. (eds.). Flora of the Venezuelan Guayana. Euriocaulaceae Lentibulariaceae. Vol. 5. Missouri Botanical Garden Press, St. Louis. Pp. 72-228.
• Webster, G.L. & Huft, M. 1988. Revised synopsis of Panamanian Euphorbiaceae. Annals of Missouri Botanical Garden 75: 1087-1144.
• Wurdack, K.J. & Davis, C.C. 2009. Malpighiales phylogenetics: gaining ground on one of the most recalcitrant clades in the angiosperm tree of life. American Journal of Botany 96: 1551-1570.
• Wurdack, K.J.; Hoffmann, P. & Chase, M.W. 2005. Molecular phylogenetic analysis of uniovulate Euphorbiaceae (Euphorbiaceae s.s.) using plastid rbcL and trnL-F DNA sequences. American Journal of Botany 92: 1397-1420.
• Wurdack, K.J.; Hoffmann, P.; Samuel, R.; Bruijn, A.; van der Bank, M. & Chase, M.W. 2004. Molecular phylogenetic analysis of Phyllanthaceae (Phyllanthoideae pro parte, Euphorbiaceae s.l.) using plastid rbcl dna sequences. American Journal of Botany 91: 1882-1900.

Publication Dates

• Publication in this collection
  30 Jan 2013
• Date of issue
  Mar 2012

History

• Received
  20 June 2011
• Accepted
  24 Nov 2011