Pollen morphology and its taxonomic significance in the genus Bomarea Mirb. (Alstroemeriaceae) - I. Subgenera Baccata, Sphaerine, and Wichuraea

ABSTRACT

Pollen morphology of 24 of the 33 species of three Bomareasubgenera, Baccata, Sphaerine, andWichuraea, was examined by light microscopy (LM) and scanning electron microscopy (SEM), or SEM alone. The studied species ofBomarea were stenopalynous, characterized by large, monosulcate monads with reticulate exine sculpture in most species. Opercula-like structures were present on the sulcus in B.huanuco and B.involucrosa. Differences in pollen size, exine thickness, and exine sculpture were observed. The studied taxa were divided into four major groups based on exine ornamentation observed under SEM: microreticulate, reticulate, coarsely rugulate, or finely rugulate-perforate. Pollen characters alone did not appear to correlate clearly with the current subgeneric classification of Bomarea, but they may have some taxonomic utility below the subgeneric level. The most reliable infrageneric classification of Bomarea can be achieved through combined analyses of morphological, palynological, and molecular data from larger samples of specimens of all the species.

Keywords:
Bomarea; exine sculpture; infrageneric classification; opercula-like structures; scanning electron microscopy