Spore morphology of Taenitis, Syngramma and Austrogramme species (Pteridoideae, Pteridaceae) from South-Eastern Asia

A comparative study of spores of seven pecies: Taenitis blechnoides (Willd.) Sw., T. hookeri (C. Chr.) Holttum, T. pinnata (J. Sm.) Holttum, Syngramma alismifolia (Presl) J. Sm., S. lobbiana (Hook.) J. Sm., S. quinata (Hook.) Carruth., and Austrogramme boerlageana (Alderw.) Hennipman from South-Eastern Asia was performed using the method of scanning electronic microscopy (SEM). Spores of all examined species are trilete, tetrahedral or tetrahedral-globose. Spores of Syngramma and Austrogramme are very similar to each other in shape and ornamentation. Ornamentation of both sides of spore is similar, verrucate (microverrucate), surface covered by rodlets and granulate deposits. Spores of Taenitis species with conspicuous cingulum (Taenitis blechnoides) or without it, ornamentation of both faces of spore could be tuberculate or baculate. Spores of Taenitis hookeri and Taenitis pinnata demonstrate tendency to forming of comissural ridges. Spore size of all studied species is close: equatorial diameter of spores of Taenitis species varies within 24–43 μm, those for Syngramma species is 29.8–35.5 μm, spores of Austrogramme boerlageana are smallest, their equatorial diameter varies within 22.5–29.4 μm.