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THE ULTRASTRUCTURE OF PALEOZOIC FERN SPORES: I. BOTRYOPTERIS
Author(s) -
MILLAY M. A.,
TAYLOR T. N.
Publication year - 1982
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1982.tb13358.x
Subject(s) - pennsylvanian , biology , fern , spore , sporangium , pteridophyte , paleozoic , botany , paleontology , structural basin
The spores of four species of the Paleozoic filicalean fern Botryopteris are examined at the ultrastructural level. Spores of B. cratis, B. forensis, B. globosa , and an unnamed species from the Lower Pennsylvanian, are compared on the basis of sporoderm stratification and the presence or absence of a sculptine layer. The species examined differ widely as to the type of reproductive unit in which they are borne and include forms that range throughout the Pennsylvanian. In all species the exine is homogeneous, lacking cavities and lamellae. A thin nexine is present in the Middle and Upper Pennsylvanian taxa, but is absent in the Lower Pennsylvanian spores. Only one spore type (B. cratis) possesses a clearly defined sculptine layer. Features of the sporoderm are compared with those of extant, homosporous pteridophyte spores.