Pollen morphology and infrageneric classification of Alstroemeria L. (Alstroemeriaceae)

Abstract

Pollen morphology of 53 taxa of the South American genus Alstroemeria was examined using light and scanning electron microscopy (LM and SEM, respectively), or SEM alone, in search of new characters that might contribute to infrageneric classification of the genus. The Alstroemeria species are stenopalynous and characterised by monosulcate and large monads with striate-reticulate exine sculpture. Pollen with auriculae-like structures at each end of the sulcus is reported for the first time in Alstroemeria. Based on exine sculpture, the studied taxa were divided into two major groups; one with striate-reticulate exine (Type I) and the other with finely to coarsely rugulate-psilate exine (Type II). Type I exine sculpture can be further divided into two sub-types based on the width of the muri. Although species from Brazil show relatively closer positions in principal component analysis of quantitative data, agglomerative hierarchical clustering of palynological features does not support a subdivision of this genus into a Brazilian and a Chilean species group. The infrageneric classification of Alstroemeria can be reliably achieved by combined analyses of morphological, palynological and molecular data from a larger number of specimens of all species.