Palynology of South American Argyrochosma and Notholaena (Pteridaceae) species

The palynology of the South American taxa Argyrochosma chilensis (J. Rémy) Windham, A. nivea (Poir.) Windham, var. nivea , var. flava (Hook.) Ponce, var. tenera (Hook. ex Gillies) Ponce and A. stuebeliana (Hieron.) Windham; N. sulphurea (Cav.) J. Sm. and N. galapagensis Weath. & Svenson has been investigated. These species show differences in spore size, shape, sporoderm thickness and structure. In both genera, the exospore is psilate and the perispore has either cristate-reticulated or reticulated ornamentation, with a complex structure and stratification. The perispore presents several characteristics useful in establishing differences valuable for taxonomic purposes. The investigated species of Argyrochosma have a perispore with a middle stratum composed of radial rodlets, and an outer continuous stratum, which bears the elements of the sculpture. These are independent of the inner structure. The spores of the investigated Notholaena species have a thick, complex, three-stratified perispore, with an outer discontinuous stratum. The middle stratum is composed of threads ramified at several levels and laterally fused. The elements of the sculpture show continuity with those of the structure. Granular material of sporopolleninous composition fills the lumina at the surface. Abnormal spores and 32 spores per sporangium were frequent in specimens of A. nivea var. nivea and N. sulphurea .