Pollen morphology of some Brazilian Xyris Gronov. ex L. (Xyridaceae) species

Abstract

Although the pollen morphology of Xyridaceae shows standard patterns that distinguish five genera, specific data of each genus are scarce or incompletely known. The pollen morphology of 17 Brazilian species of Xyris (Nematopus Section) based upon 47 specimens from Goiás and Minas Gerais States, Brazil, is presented. Micrographs of pollen grain structures were obtained using light and scanning electron microscopy. Pollen grains are characterized as monads, medium to large sized, ellipsoidal in polar view, flattened/convex in equatorial view and monosulcates. The sulci are pontoperculate and covered with an insulae type membrane. The sexine presents either a microreticulum or rugulae with perforations, and is thicker than the nexine. Although Xyris is a stenopalynous genus, characterized by monosulcate pollen grains, two groups of species were recognized based upon pollen size as well as pollen wall ornamentation features. Therefore, pollen data are of taxonomic value and useful to clarify the delimitation of the studied species.

Pollen Morphology of Convolvulaceae from Southeastern Amazonian Cangas and Its Relevance for Interaction Networks and Paleoenvironmental Studies

“…In addition, quantitative data (morphometry) confirm that the attributes used are suitable to classify the pollen types. Statistical methods such as PCA have been frequently used to evaluate the systematic utility of pollen data [ 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. For example, I. goyazensis and I. decora presented conflicts in their taxonomic delimitations [ 71 ].…”

Sistemática do complexo Xyris teres L.A. Nilsson (Xyridaceae)

“…Paraná (LOZANO et.al 2018); bem como com a descrição de novas espécies (WANDERLEY 1983(WANDERLEY , 1986(WANDERLEY , 2010WANDERLEY & CERATI 1987B;WANDERLEY & GUEDES 2011;MOTA & WANDERLEY 2013A, 2013B;LOZANO et al 2016;WANDERLEY & CAMPBELL 2017). Atualmente, é a principal especialista da família na América do Sul, trabalhando não somente com a taxonomia do grupo, mas também em áreas afins, como anatomia (WANDERLEY & CERATI 1986) palinologia (LUZ et al 2015) e citogenética (Iseppon & Wanderley 2002), além de formar novos especialistas na família MOTA et al 2015;LOZANO et al 2018), com o intuito de melhorar o conhecimento das Xyridaceae na flora brasileira.…”