. Catalogue of the fossil plants of the Glossopteris flora in the Department of geology. Paleobotany -- Carboniferous; Paleobotany -- Catalogs and collections; Plants, Fossil -- Catalogs and collections. GLOSSOPTEIUS. 51 Apex obtuse, rounded, or obtusely pointed. Frond usually some- what contracted at the base, or more rarely only very slightly contracted. Midrib broad, extending to the apex, or breaking up into fine reticulations at a short distance before reaching the apex. Secondary nerves generally arched, more rarely oblique, reaching the margin at an open angle. The obliquity of the nerv
. Catalogue of the fossil plants of the Glossopteris flora in the Department of geology. Paleobotany -- Carboniferous; Paleobotany -- Catalogs and collections; Plants, Fossil -- Catalogs and collections. GLOSSOPTEIUS. 51 Apex obtuse, rounded, or obtusely pointed. Frond usually some- what contracted at the base, or more rarely only very slightly contracted. Midrib broad, extending to the apex, or breaking up into fine reticulations at a short distance before reaching the apex. Secondary nerves generally arched, more rarely oblique, reaching the margin at an open angle. The obliquity of the nervation varies greatly even in portions of the same frond, and the size of the meshes also varies considerably. The network is as a rule fairly open, the meshes being polygonal, or elongate-polygonal. Glossopteris Browniana varies greatly in size, shape, and in the details of the nervation. An average spathulate frond measures between 13 and 15 cm. in length. Other fronds are as small as. Fig. 16.—Glossoptcris Browniana, Brong. Nervation of fronds from Australia. After Zeiller. X 2. 2 5 cm. long. Sehiinper' has called attention to the variety in the form and shape of these fronds. More recently Zeiller3 has studied in detail the variation in the nervation, variations which he regards as individual and non-specific. He has pointed out that the midrib is not always found to be present at the base of the frond, but that it may be replaced by a group of parallel nerves, in this respect recalling Gangamopteris. The obliquity of the secondary nerves and the breadth of the meshes also vary greatly (Text-fig. 16). The meshes may be fairly broad and almost equal in size, or broader in the neighbourhood of the midrib. Or they m iy be narrow, and approximately of equal size throughout. Schiniper (69), vol. i, p. 646. Zeiller (96'), p. 3G2, figs. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an
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