Morphological and ultrastructural variations in <i>Scliizjaea pectinata</i> (Schizaeaceae: Pteridophyta)

Abstract

Schizaea pectinata (L.) Sw. was collected from the extreme ends of its geographical range in South Africa for a study of sporangial development, sporogenesis and tapetal organisation. Differences were noted in the gross morphology , in sporangium size, spore size and in the patterning of the outer exospore from the two sites. Coiled structures were associated with the development of the inner perispore in spores collected from the Transvaal, whereas dense, heterogeneous bodies were associated with the formation of this layer in spores from the Cape. Differences were also noted in the organisation of the tapetum. A cellular, parietal tapetum and a plasmodial tapetum were present in the Cape material when the spores had developed the sculptured outer exospore. In sporangia from the Transvaal, however, only a plasmodial tapetum was present at the same stage of sporoderm development. A detailed study of S. pectinata throughout its distribution is required to determine the taxonomic importance of these findings.

Spore wall ultrastructure inAnogrammaspecies (Pteridaceae) from Argentina

“…The spherules are small bodies with a concentric arrangement of the different perisporal materials as defined Tryon & Lugardon (1991, p. 9) in Schizaea J. E. Smith and Salpichlaena J. Smith. Similar bodies have been shown in Schizaea pectinata (L.) Sw. from South Africa by Parkinson (1994). Lugardon (1981) defined globules with a similar structure as free or captive and mentioned that they could be found in many genera of Filicophyta.…”

Micromorphology of outer exospore coatings inSelaginellamegaspores

“…If our suggestion that silica is widespread in Selaginella, then both genera share a siliceous outer coating, followed by an (outer and inner) exospore, an inner separable layer and the intine [terminology following Taylor (1989)]. Moreover, habitat is a known factor for intraspecific variability, as described for Schizaea pectinata L. (Sw.) spores by Parkinson (1994). Her work demonstrated that S. pectinata species from two very different South African habitats show noticeable differences in spore morphology and ultrastructure.…”

Morfología y ultraestructura de las esporas de Schizaea fistulosa (Schizaeaceae) de Chile.

“…On the other hand, spore development studies in other species of this genus as Schizaea pectinata from South Africa (Parkinson, 1994(Parkinson, , 1995a, described a two-layered exospore and also a two-layered perispore.…”

“…Later, Parkinson (1994) studied the spore wall development in Schizaea pectinata from South Africa. The author described the species sporoderm as having a two-layered exospore and a two-layered perispore.…”