一些中国蕨类植物的细胞学观察

本文报道华东地区30种蕨类植物的染色体数目，其中阔片短肠蕨Allantodia mathewi(Cop．) Ching n＝82, 耳羽短肠蕨A．wichurae(Mett．)Ching n=41，拟粉背蕨Aleuritopteris pseudof- arinosa Ching n＝58，刺头复叶耳蕨Arachniodes exilis(Hance)Ching n＝41，斜方复叶耳蕨A． rhomboides(Wall．)  Ching n＝41，毛轴假蹄盖蕨Athyriopsis  peterseni(Kunze)Ching n＝80， 园盖阴石蕨Humata tyermanni Moore n＝40,  峨眉茯蕨  Leptogramma scallanii(Christ)Ching n=36,福建剑蕨  Loxogramme  fujianensis Ching n＝35，黄腺羽蕨Pleocnemia  winitii  Holtt．   n＝41，紫柄蕨Pseudophegopteris Pyrrhorachis(Kunze)Ching n=62是首次报道。     

中国蕨类植物染色体数目的观察

The present paper is a first instalment on the Chromosome counts by the authors of Chinese ferns, representing 13 species collected from the eastern coastal provinces of China.  Our findings agree pretty well with the previous ones by botanists mainly in Japan.  The voucher specimens for the present study are all preserved in the Depart- ment of Biology, the East China Normal University, Shanghai.      We wish to thank Professor R. C. Ching for his constant encouragement andguidance in the study of Chinese fern cytology.     

我国荒漠植物区系形成的探讨

    1.  Based upon the analyses in the floristic elements of the three genera (Suaeda, Salsola and Zygophyllum) in different regions we can see that the genesis of our desert floras in these regions is very much diversified.  The flora of Songaria is similar to that of the Middle Asia, while the Hosi Corridor seems to be a transitional area very close to Alashan and also related to the Tarim Basin in floristic elements. Thus, we may classify the desert floras into three parts: the flora of Songaria, of Alashan including the Hosi Corridor and of the Tarim Basin including the Tsaidam Basin. The ages and approa- ches in their formation are different.      2. There are plenty species but no or rare endemics in Songaria. In spring there are a number of ephemeral plants. The variation of aspect is evident.  The vegetation cover is abundant. The floristic elements are developed from the flora of Middle Asia and it was formed in Quaternary period.      3. The floristic elements of the Tarim Basin are poor, but there are not few en- demics and the distribution of the endemics is much limited.  They are of the charac- teristics of relic species.  Therefore it was formed in the Tertiary period and developed in Quaternary period.  The elements are related to the Mediterranean flora.      4.  There are a large number of endemics and many endemic monotypie genera in Alashan.  They represent the flora formed in Tertiary period. Although it is of a special style, it relates both to the Middle-Asian and the Mediterranean flora.      5. The historic causes for the formation of the different floras lie chiefly on: (1) The rise of the Tibetan plateau and mountains strongly changed the climatic and edaphic conditions and in the long course of evolution some species survived or even developed, while the others deteriorated or even died out from the flora. (2) Because the circum- stances of transgression or regression of the Tethys were different in these regions. (3) The mountain-making movement, the transgression and regression and the fluence of glaciation, all the mutation of these associated factors modified the climatic zonation and then the plant species changes followed, new species formed and migration of floristie elements occurred. (4) Songaria is the nearest region to the then Sibirian glacier, so the frozen injury to the flora might be the greatest. (5) In the Glacial period the descension of snow line in Songaria was greater than that of the Tarim Basin, so the frozen injurymight be greater.