Morphology and ultrastructure of Sphaeropteris spores (Cyatheaceae) from the Neotropics

Spores of species of Sphaeropteris genus from America were studied with TEM and SEM. Six species were quoted as growing in America (cf. Tryon, 1971; Windisch, 1977): Sphaeropteris brunei (Christ) Tryon, Sphaeropteris cuatrecasacansii Tryon, Sphaeropteris gardneri (Hook.) Tryon, Sphaeropteris horrida (Liebm.) Tryon, Sphaeropteris insignis (D. C. Eaton) Tryon and Sphaeropteris quindiuensis (Karst.) Tryon. The aims are to characterize the species through their spore morphology and sporoderm ultrastructure. Based on these results it speculates about the relationships of these taxa within the family Cyatheaceae. It was find out with SEM, three kinds of surfaces can be recognized. It was find out with TEM that the exospore and perispore have two layers. The perispore is composed of an inner layer with three strata and the outer layer has two strata. The palynological characteristics were important in the identification of a natural taxonomic group.