Análises ontogenéticas do pericarpo de espécies de Mimosa Linnaeus (Fabaceae, Mimosoideae)

Abstract

-(Ontogenetic analysis of the pericarp of species of Mimosa Linnaeus (Fabaceae, Mimosoideae)). The objectives were to analyze ontogenetically the fruits of Mimosa daleoides, M. dolens var. anisitsii and M. orthacantha, comparing themselves and identifying them correctly. Collections were made in Botucatu, São Paulo State, Brazil, and the fruits in several development stages were prepared according to usual anatomical techniques. During pericarp development, dendritics and spine-like emergences are produced, and an adaxial meristem is installed, originating the multiseriate lignified outer endocarp and the uniseriate parenchymatous inner endocarp. The structure of pericarp follows the pattern for Fabaceae, with uniseriate exocarp, parenchymatous and vascularized mesocarp, and heterogeneous endocarp. In M. daleoides and M. orthacantha, false septa are formed where transverse fragmentation of the pericarp occur; moreover, lignified tissue is produced externally to the ventral and dorsal bundles. Therefore, the fruits of these two species are craspedium and M. dolens var. anisitsii produces legumes with passive dehiscence. Keywords: anatomy, fruit, Mimosa, morphology, ontogenesis RESUMO -(Análises ontogenéticas do pericarpo de espécies de Mimosa Linnaeus (Fabaceae, Mimosoideae)). Os objetivos foram analisar ontogeneticamente frutos de Mimosa daleoides, M. dolens var. anisitsii e M. orthacantha, compará-los e classificá-los corretamente. Coletas realizadas em Botucatu, SP, Brasil, renderam frutos nos vários estádios de desenvolvimento, preparados segundo técnicas anatômicas usuais. Durante o desenvolvimento do pericarpo, emergências dendríticas e espiniformes são formadas, e um meristema adaxial é instalado, originando o endocarpo externo, multisseriado e lignificado na maturidade, e o interno, unisseriado e parenquimático. A estrutura do pericarpo segue o padrão para as Fabaceae, com exocarpo unisseriado, mesocarpo parenquimático e vascularizado, e endocarpo heterogêneo. Em M. daleoides e M. orthacantha, formam-se falsos septos, onde o pericarpo fragmenta-se transversalmente; além disso, tecido lignificado forma-se externamente aos feixes ventrais e ao dorsal. Os frutos destas duas espécies são, portanto, craspédios e Mimosa dolens var. anisitsii forma legumes com deiscência passiva.

Plants at the summit: characterization of grasslands on cerros chatos of northeastern Uruguay

“…When available, earlier exsiccates from those sites deposited at the MVFA and MVJB herbaria were also included as vouchers for the species list. Taxa were tentatively identified in the field, and later confirmed using pertinent taxonomic literature (Rosengurtt, 1970;Burkart et al, 2005;Lezama & Bonifacino, 2012;López, 2012;Zuloaga et al, 2012;Zuloaga et al, 2014;Silveira, 2015;Brazilian Flora Group, 2021) and herbarium specimens hosted at MVFA. All samples collected were deposited at MVFA herbarium.…”