Scientia Sinica

146 SCIENTIA SINICA Vol. V

of the pinnules displayed in Cl. shenstensis obtained from the Yenchang formation of Northern Shensi.. But apart from minor differences, these two species might be classed under one morphological type. The specimen of ?Sphenobaiera furcata (Heer) Florin of the Yenchang flora bears a strong resemblance to the species of Basel which was first described by Heer (1865)"! as Sclerophyllina furcata and later transferred by the same author (1877)" to Baiera. In 1936, Prof. Florin!’ referred this species to Sphenobaiera. In 1943, Prof. Krausel"! described many better preserved specimens from Basel, finding that the epidermal and stomatal structure of this species belongs evidently to the Sphenobaieratype. It is of interest to point out that the epidermal structure of our specimen can also be compared more or less with that of the Basel species. The species Ginkgoites chowz sp. nov. agrees fairly well with Ginkgoites lunzensis (Stur) Florin'’"! from Lunz, Austria, in regard to the size of the leaf with coarse venation. It is highly possible that future investigations of our localities may reveal similar specimens of Lunz with the characteristic truncate segments''!. The species Cladophlebts szeiana P’an in the present material, though no doubt a distinct one, is closely comparable with Merianopteris angusta'"” *) of Basel. This species was also described by Krasser'! in the Lunz flora. He changed its specific name to Asterotheca meriam (Brongniart) Stur and placed the species Asterocarpus virginiensis Fontaine in the same Synonym-list. All geologists and palzobotanists now generally agree that the age of the Virginia-Keuper of North Arnerica is equivalent more or less to the Basler Keuper and Lunzer Keuper in Europe and that all these three formations belong definitely to the Middle Keuper age. If the species Asterocarpus virginiensis Fontaine from the Virginia-Keuper™! is really identical with Asterotheca meriani (Brongn.) Stur (=Merianopteris angusta Heer) from the Basler Keuper and Lunzer Keuper in Europe, our species Cl. szetana can also be compared with Asterocarpus virginiensis of North America and its fructification may also belong to the Asterotheca type. According to P’an’*!, our species is more closely comparable with the form Asterocarpus virgimiensts var. obtusilobus of Virginial”!, It seems to the present writer that not only do the sterile but also the fertile pinnae of our species remind us of those of the American species. Cl. szeiana is also similar to Asterocarpus platyrachis Fontaine!™! of North America, which, according to Krasser'!, is also identical with Mertanopteris angusta Heer of Europe, and can also be placed in the same synonym with Asterotheca meriani (Brongn.) Stur. The other species of the Yenchang Formation which show a relationship to the Virginia flora of North America need also be mentioned. Cladophlebis graciles Sze recalls Cladophlebis microphylla Fontaine from the Virginia Keuper''™”, and it is also comparable with Cl. pseudowhitbiensis Fontaine from the same locality'*!. In regard to . the size of the pinnae, our Sphenozamites changi Sze is perhaps more closely related to Sphenozamites rogersianus Fontaine’? than to any other known fossil plants, in spite of the fact that the shape of the pinnae of the American