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Abstract
The spores of seven Cheilanthes Sw. species that grow in the Northwest Region of Argentina were studied with LM, SEM and TEM.
They were: Cheilanthes margínala H. B. K., C. micropteris Sw., C. myriophylla Desv., C. notholaenoides (Desv.) Weath., C. pilosa Gold., C. poeppigiana Mett. ex Kuhn, and C. pruinata Kaulf.
C. volcanensis de la Sota, mentioned for the region, was not included because all the collected material was sterile or immature.
The equatorial diameter is not useful in distinguishing species because of the interspecific variability of such species as C. micropteris, C. poeppigiana and C. pruinata. In other cases interspecific variation overlaps.
All the species analysed here have one basic pattern of structure: a homogeneous, smooth exospore and a sculptured perispore.
The perispore has two layers: an innermost one, granular, compact and an outermost one, reticulate with or without an outer lamella. The outermost layer constitutes the greatest part of the perispore.
Five sculpture groups were distinguished: rugulose, ridged, cristate, cristate-reticulate and tridimensionally reticulate.
One new type of sculpture is mentioned in Cheilanthes: ridged.
