Palynological analysis of the genus Ctenitis (C. Chr.) C. Chr. (Dryopteridaceae) in the Southern Cone of America

Abstract

The spore morphology and wall ultrastructure of 12 species of Ctenitis from Southern Cone of America were studied using light microscope, scanning and transmission electron microscope. The study was carried out with herbarium material from Argentine and Brazilian institutions. Equatorial diameters, polar diameters and laesura length were measured. The spores are monolete with echinate or folded ornamentation. In the echinate type, the spines are conical, with broad base and attenuate apex. In the rugate type, the folds are infl ated, linear, sinuous, subglobose or handle-shape. The perispore surface is scabrate, rugulate, microverrucose or psilate. Stratifi cation and ultrastructure in the species analyzed are very similar. The exospore is smooth and two-layered in section. Simple and branched channels are observed mainly in the outer exospore. The perispore is composed of two layers, the inner one forms the ornamentation and the outer covers all the outer and inner surfaces. Immature spores were found in all samples of C. fenestralis. The characteristics of the studied spores like macro-ornamentation, color and fold length provide relevant information to differentiate some species or groups of species within the genus.

Palynomorphometry in ferns: Ctenitis (Dryopteridaceae), a case of study in the Southern Cone of America

“…The results obtained were on the same line with what was described by Viveros et al (2018) and Gorrer et al (2022). Complementary to these studies, a series of relatively unexplored quantitative characters in spores, in general, and in the Ctenitis genus, in particular, such as length, width and height of the folds, are here introduced.…”

“…Other examples are the sporophytes of Ctenitis bigarellae, C. falciculata, C. paranaensis and C. submarginalis which are morphologically similar (Viveros et al 2018). However, the data presented by Gorrer et al (2022), together with the data presented here, show some differences among the spores. C. bigarellae and C. submarginalis have spores with short, subglobose and inflated folds but they are differentiated by color.…”

“…However, two of them present aborted spores, and another two show spores not seen so far (Viveros et al 2018). Of the remaining 11, only one has equinated spores and the other ten species have folded spores (Gorrer et al 2022).…”

“…Spore morphology of fern species has been observed and described under light microscopy (LM) and scanning electron microscopy (SEM) in previous studies (e.g., Nayar & Devi 1964;Gastony 1974;Morbelli 1976;Tryon & Lugardon 1991;Giudice et al 2004;Moran et al 2007;Ramos Giacosa et al 2015, 2016Gorrer et al 2020Gorrer et al , 2022. In these studies, differences in shape, size, aperture characters and wall ornamentation were reported.…”

“…Since morphometric knowledge about the spores of the genus has not yet been deepened, the proposal of this work is the incorporation of new micromorphological characters to provide more evidence for the delimitation and/or grouping of species in the genus. Considering the morphology of the folded spores of the Ctenitis which inhabit the Southern Cone of America and complementing the study carried out by Gorrer et al (2022), the aims of this study are: 1) to increase infrageneric knowledge, 2) to evaluate the relationship among the morphometric characters of the folded spores in these Ctenitis species, and 3) to verify the spores morphometry as a taxonomic tool.…”