The Isoetes Page

Website of the Isoetes Research Group

Micromorphological approach to the systematics of Mediterranean Isoëtes species (Isoëtaceae, Lycopodiophyta): Analysis of the megaspore surface

Publication Type:Journal Article
Year of Publication:2012
Authors:A. Troia, Bazan, G., Schicchi, R.
Pagination:35 - 43
Date Published:2012///
Keywords:energy-dispersive X-ray spectroscopy (EDS), Isoëtes duriei, Isoëtes histrix, Isoëtes sicula, Isoëtes todaroana, Isoëtes velata, SEM, Sicily, siliceous coating

Megaspore ornamentation is one of the few morphological characters used in the taxonomy of the genus Isoëtes. In the present work, we test the application of this character for distinguishing some Isoëtes species occurring in the Mediterranean: Isoëtes sicula, which according to some authors should be included as a variety in I. histrix, and the recently described I. todaroana, whose affinity with other taxa is currently unknown. Two additional species (I. duriei, I. velata) were also included in the analysis. The megaspores were studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and chemical treatment. In all species, the megaspore surface is covered by a siliceous coating; removal of this coating reveals an underlying three-dimensional network of fused rodlets. A unique pattern of this network occurs in I. sicula, supporting its separation from I. histrix. Comparison between the patterns observed in the examined Mediterranean species shows that I. todaroana is most similar to I. histrix. © 2012 Copyright 2012 Collegium Palynologicum Scandinavicum.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith