5 research outputs found
Notes on some Glossopteris species from Hammanskraal (Transvaal)
Main articleThe study of Glossopteris began with the mistake that two half fronds were glued together as one and that specimen was chosen as the holotype of one of the first Glossopteris ever described, Glossopteris browniana var. indica Bngn. The mistake led to confusion and even to distrust of the possibility of identifying Glossopteris species on frond impressions only. As most of the GIossopteris remains are such, and the
literature from Brongniart onwards is mainly based on them, the frond morphography is bound to be the starting point of the classification. The present paper shows that (a) with the examination of greater numbers of specimens, it is possible to select the specific characters and to learn the individual variations and (b) identifications can only be based on the original descriptions and figures of the taxa.Non
SEED-BEARING GLOSSOPTERIS LEAVES
Seeds are commonly known elements of
Glossopteris floras. The connection of these seeds to
any definite elements in the floras and their
systematic position with it has always been uncertain,
and they are usually referred to as a group
"incertae sedis". Several of these seeds have been
described and placed in the genera Cardiocarpus
Brongniart, Cordiocarpus Geinitz and Samaropsis
Goeppert, specially erected for them. Arber (1905, p .
206) noticed the common occurrence of seeds with
Glossopteris leaves, and refers to them without any
further conclusion as "A few seeds .. . in association
with fronds of Glossopteris broumiana. The seeds are
possibly referable to Cardiocarpus"
Clarification of the genus Palaeovittaria Feistmantel
Ever since the genera Palaeovittaria and Noeggerathiopsis were first established it seems that separating them has posed problems for many palaeobotanists, yet the original definitions noted clear and unambiguous generic differences in their leaf venation; these characters are now applied in the identification of South African leaves. In Palaeovittaria leaves the veins run toward the margin over the entire length of the lamina, and they radiate fan-wise in the apical portion. In Noeggerathiopsis, on the other hand, the veins appear to run parallel to the margins over the whole length of the lamina, from base to apex, and they intersect the margin only in the apical region. Interpretation of the chronostratigraphic distribution of Palaeovittaria Feistmantel, 1876 has also been problematical. It has been regarded on the one hand as a genus restricted to late Permian floras, and on the other as a very early member of Glossopteris floras, thus implying an early Permian age. The reason for this discrepancy is discussed. It is concluded that by direct interpretation of the available data, Palaeovittaria must be regarded as a late Permian taxon
Clarification of Belemnopteris Feistmantel 1876, and description of a leaf of Belemnopteris pellvcida Pant and Choudhury 1977 found amongst a South African Ecca flora
A leaf of Belemnopteris pellucida Pant and Choudhury 1977 was found for the first time in South Africa amongst an Ecca flora near Hammanskraal, about 30km north of Pretoria. The taxonomic status of Belemnopteris Feistmantel 1876 and the biostratigraphic correlation indicated by the presence of this genus is clarified