为解决早三叠世卡以头组地质时代和植物组合问题，对采于黔西滇东地区两条二叠系-三叠系海陆交互相界线剖面卡以头组中、下部的植物化石Annalepis（脊囊属）进行深入研究。与Annalepis同层或上部层位见有早三叠世早期的海相双壳类、介形类、腕足类、菊石类及大羽羊齿植物群残余分子，因此可以确定Annalepis在该地区出现于早三叠世早期的印度期（Induan），说明卡以头组（至少中、下部）地质时代属早三叠世早期。推测我国南方的Annalepis在早三叠世始于黔西滇东，随后向北迁移、中三叠世广布于长江中下游地区。建立由早三叠世Annalepis和大羽羊齿植物群残存分子共同构成的我国南方早三叠世早期植物组合，填补了早三叠世晚期岭文组与晚二叠世B期Gigantonoclea guizhouensis—Ullmannia cf．bronnia-Annularia pinglouensis组合之间的空白。

Most of South China was in a vast expanse of ocean during the Early-Middle Triassic due to which the fossil plants are quite rare there.In studying the floras of this area,one was always struck by the absence of the Early Triassic plants.In the recent years,however,the paleobotanists continuously reported that fossil plants were discovered in late Early and Middle Triassic series.Numerous dispersed and well-preserved fossil plants reported in this paper were all collected from the lower part of Kayitou Form...

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