ABSTRACT
Plant communities on rock outcrops in brazilian semiarid are still largely unknown to science. The country Quixadá, in the semiarid of the state of Ceará, is distinguished by the great concentration of rock outcrops. This study aims to know the composition, the life-form and the strategies of dispersal of the species in an inselberg the country of Quixadá and the similarity with surrounding caatinga. In the 2000 year, monthly collects of the flora were carried out and the life-forms and dispersal syndromes were classified in an area situated on 4° 57' S and 39° 01' W, 270 m. a.s.l. The similarity of the flora of the surrounding was analyzed through the Jaccard index. Seventy-seven species, 66 genera and 36 families had been inventoried. The percentages of the life-form spectrum and the dispersal spectrum represented were: therophytes (44,2), phanerophytes (24,7), chamaephytes (14,6), hemicryptophytes (13,4), geophytes (2,6), aerophytes (1,2) and anemocoric (49), autocoric (35) and zoocoric (16). The similarity with the flora of the caatinga surrounding was 13% (21 species), what it demonstrated that the vegetation surrounding is the main source of propagules. The therophytes are the dominant life-form in inselbergs of semi-arid regions, whose flora also is predominantly dispersed for abiotic factors, mainly the wind. This study confirms the expected patterns about dispersal and life-form spectrum of the arid and semiarid vegetation.
Key words:
rock outcrops; semiarid; flora; life form; caatinga