SEM images, quantitative analysis code of SEM images, and data analysis code for "Grass pollen surface ornamentation is diverse across the phylogeny: evidence from northern South America and the global literature"

The grasses are one of the most diverse plant families on Earth, however, their classification and evolutionary history are obscured by their pollen stenopalynous (similar) morphology. A combination of high-resolution imaging of pollen surface ornamentation and computational analysis has previously been proposed as promising tool to classify grass taxonomic boundaries. In this study, we test this hypothesis by studying Poaceae pollen across the phylogeny from plants collected in northern South America, but also from published literature across the globe. We assessed if morphotypes that we establish using descriptive terminology are supported by computational analysis, if they vary along six (a)biotic variables and how vary across the phylogeny. Based on this analysis, we constructed a reference framework for pollen surface ornamentation morphotypes. Our results showed that there is a very wide variation of grass pollen surface ornamentation. We identified nine new and six known morphotypes and established our dataset of 223 species (243 individual plant specimens) from 11 subfamilies. Computational analysis showed that our morphotypes are well-supported by two quantitative features of pollen sculptural elements (size and density). The specific dataset and mapping of the phylogeny confirmed that pollen morphological sculpture is unrelated to (a)biotic variables but is diverse across through the phylogeny.