Trichomes are key functional traits that protect plants against abiotic stresses, herbivores and pathogens. In addition to their ecological roles, trichomes show high morphological variability in many lineages, providing useful characters for species characterization and taxon delimitation. Here, we focus on trichomes in Croton, a megadiverse genus (c. 1200 spp.) of Euphorbiaceae, in which these structures are ubiquitous and exhibit significant variation in form, location on the plant body, density and function. Owing to their functional and taxonomic relevance and the current need for further standardization of their terminology and classification, we revised previous trichome classifications used in the genus. We also provide new trichome data by expanding taxon sampling and using different methodological approaches in plant anatomy to improve understanding of the structural patterns of the trichome types present in the genus. On the basis of our results and literature review, we propose a new classification for trichomes in Croton based on well-defined parameters; this clarifies existing redundancies, is consistent with anatomical evidence and can be easily updated as new types are revealed in future surveys. This contribution will improve communication among taxonomists and promote more meaningful morphological comparability across systematics studies, including those focusing on morphological evolution and functional traits.
O estudo apresenta a descrição anatômica foliar de Barnebya, um gênero endêmico do Brasil com apenas duas espécies. O objetivo deste trabalho foi descrever a anatomia foliar e identificar características diagnosticas para a taxonomia e sistemática deste gênero. Folhas herborizadas das espécies B. dispar (Griseb.) WR Anderson & B. Gates e B. harleyi WR Anderson & B. Gates foram reidratadas e processadas de acordo com os métodos anatômicos usuais para análise em microscopia de luz. Os caracteres anatômicos foliares diagnósticos são: a presença e o número de feixes acessórios no pecíolo, conformação do feixe vascular da nervura central, presença de tricomas, presença de ornamentação na parede externa de células epidérmicas na face abaxial do limbo foliar e os tipos de monocristais. Os resultados obtidos no presente estudo mostraram e ressaltam que caracteres anatômicos relacionados a pecíolos são importantes na caracterização de gêneros e caracteres relacionados a lâminas foliares são importantes na caracterização de espécies em Malpighiaceae, corroborando estudos anteriores e realizando pela primeira vez a descrição anatômica foliar de Barnebya.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.