Variation in morphology of the pistillate flowers of Astrocaryum urostachys (Palmae) in Amazonian Ecuador

The variability of pistillate flower qualitative morphology and size in the palm species Astrocaryum urostachys in the Ecuadorean Amazon is analysed. In total 4393 flowers were sampled from 145 inflorescences born on 135 individual palms. Sampling was performed in 4 regions, north, western centre, southwestern centre and, south. The results show that (i) qualitative morphology and relative proportions of flower parts are weakly variable, (ii) size of pistillate flowers is very variable within the total sample, within a region, within an individual palm and even within one inflorescence, (iii) no significant difference exists in flower size between the northern, western central and southwestern central regions, and (iv) there is a significant tendency to produce smaller pistillate flowers in the southern region. The low variation in qualitative morphology and in the relative proportions of pistillate flower parts within Astrocaryum urostachys provides new arguments in favour of the relevance of these characters in the taxonomy of Astrocaryum section Ayri.