Spore morphology and wall ultrastructure of Lycopodiaceae from northwest Argentina

• Published in: Review of palaeobotany and palynology 2016-02, Vol.225, p.84-94
• Main Authors: Ramos Giacosa, J.P., Morbelli, M.A., Giudice, G.E., Gorrer, D.A.
• Format: Article
• Language: English
• Subjects: Argentina; Lycopodiaceae; Lycopodium clavatum; Morphology; Saururus; Spore; Ultrastructure
• ISSN: 0034-6667; 1879-0615
• DOI: 10.1016/j.revpalbo.2015.11.009

Spores of Lycopodiaceae species growing in northwest Argentina were studied. The taxa are: subfam. Lycopodioideae: Austrolycopodium erectum, Diphasiastrum thyoides, and Lycopodium clavatum subsp. clavatum; subfam. Lycopodielloideae: Palhinhaea cernua; and subfam. Huperzioideae: Phlegmariurus mandiocanus, Phlegmariurus phylicifolius, Phlegmariurus reflexus, Phlegmariurus saururus, and Phlegmariurus sotae. The study is based on herbarium material; spores were examined with light microscope (LM), scanning (SEM) and transmission electron microscope (TEM). Spores are trilete 24–44μm in equatorial diameter and 14–35μm in polar diameter. The exospore is 0.5–9.5μm thick and one or two-layered, depending on the analyzed area of the spore. The ornamentation can be reticulate, rugulate, foveolate, fossulate or foveolate–fossulate. The perispore is 30–190nm thick, one or two-layered, and is only visible with TEM. The presence of this wall is mentioned and described for the first time in Phlegmariurus phylicifolius. In the studied species, spore ornamentation of the proximal face is different from or less complex than the distal face. The results evidence the significance of spore morphology in Lycopodiaceae systematics, particularly at subfamilial level. •The spore morphology is a stable character in the genus Phlegmariurus.•Perispore is only visible with TEM.•Perispore is mentioned and described for the first time in Phlegmariurus phylicifolius.•There is a correspondence between the spore ornamentation and the subfamilies of Lycopodiaceae.