异叶苣苔属地上茎的生长式样及其系统发育意义

对异叶苣苔属植物地上茎形态发生过程的观察旨在揭示该属地上茎的生长式样。该研究发现异 叶苣苔属植物地上茎的生长式样并不是以往所认为的简单顶端生长。该属植物的顶芽已完全受到抑制。其地上茎实际上是萌发于小型叶叶腋的侧芽替代顶芽生长所形成的各级侧枝系统，即合轴分枝系统。异叶苣苔属植物地上茎的不分枝情况是位于大型叶叶腋的腋芽受到抑制所致，纯粹是一种次生现象，并不是尖舌苣苔族植物原始祖先的孑遗性状。尖舌苣苔族其他属植物地上茎的生长式样并不均是从异叶苣苔属植物的生长式样演化而来。出蕊苣苔属和异叶苣苔属植物地上茎的生长式样可能来自同一个不太远的祖先，但已经向着不同的方向演化。独叶苣苔属植物复杂的圆锥状对花聚伞花序并非从异叶苣苔属地上茎上部，即生殖生长部分退化而来，乃幼态成熟的复化过程所致。尖舌苣苔属的总状花序可能更接近尖舌苣苔族的原始祖先类型。

The growth pattern of shoots in Whytockia (Gesneriaceae) with phylogenetic implications

The morphogenesis of shoots in Whytockia W.W.Smith was investigated in order to reveal its growth pattern. The shoot in Whytockia has lost apical growth, which is contrary to the present knowledge about its growth pattern. Its stem is in fact a lateral branch system formed by sprouting of lateral buds in axils of small leaves substituting for the thoroughly restrained phyllogens. The unbranched stem of the genus is due to the restrained state of axillary buds in axils of large leaves. This so called simple stem is secondary in phylogeny rather than relict in Epithemateae. According to the revealed growth pattern of the shoot in Whytockia, the present paper discusses the phylogenetic relationships between Whytockia and Loxonia, Monophyllaea and Rhynchoglossum in Epithemateae.