Micromorphological approach to the systematics of Mediterranean Isoetes species (Isoetaceae, Lycopodiophyta): analysis of the megaspore surface

作者：Troia Angelo^*; Bazan Giuseppe; Schicchi Rosario

来源：Grana, 2012, 51(1): 35-43.

DOI：10.1080/00173134.2011.637131

• SEM
• energy-dispersive X-ray spectroscopy (EDS)
• Sicily
• siliceous coating
• Isoetes duriei
• Isoetes histrix
• Isoetes sicula
• Isosetes todaroana
• Isoetes velata

Megaspore ornamentation :s one of the few morphological characters used in the taxonomy of the genus Isoetes. In the present work, we test the application of this character for distinguishing some Isoetes species occurring in the Mediterranean: Isoetes 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.

• 出版日期2012