VII. On some pteridospermous plants from the Mesozoic rocks of South Africa

This paper forms a further contribution towards the elucidation of the nature of the floras of Mesozoic times and of the affinities and systematic position of the plants composing them. When the author commenced work on this subject in 1910, a number of form genera of leaves had for many years been considered to represent the remains of ferns, though no fertile specimen had ever been found. It has since been shown that one of the most ubiquitous form genera, Taniopteris, included several species which were the fronds of bennettitalean seed plants (Thomas, 1915). Subsequently the form genus Sagenopteris was shown to be the leaf of a primitive angiospermous type, the Caytoniales, and not a fern frond (Thomas, 1925). We now come to deal with a group of plants whose leaves have been known for a long time under the names of Thinnfeldia and Lepidopteris. Here again we have evidence that these somewhat fern-like leaves belonged to seed-bearing plants