宽叶兔儿风花序侧生分枝的变异式样以及分枝兔儿风的分类地位问题

宽叶兔儿风Ainsliaealatifolia花序主轴上的侧生分枝通常被描述为由单个或2–4个头状花序聚集而组成的簇生花序。作者在野外和标本馆中仔细研究了该种居群内侧生分枝花序形态的变异,依据其简化和集中的程度在居群内区分出3种花序类型:简单的复合聚伞花序、复杂的复合聚伞花序以及两者之间的过渡类型,具有后面两种类型的个体在居群内少见。这一发现不仅为探讨兔儿风属内各种花序的演化提供了新的线索,而且为理清宽叶兔儿风这一地理广布种的分类学问题提供了新的视野。居群内有些侧生分枝为复杂的复合聚伞花序类型的个体整个花序的主轴折断了,这是由于整个主轴顶端部分被昆虫蛀食或者其他外力造成的。值得注意的是分枝兔儿风Ainsliaealatifoliavar.ramifera的主模式就属于这种情况。分枝兔儿风和宽叶兔儿风原变种之间在分布区、生境以及物候上并没有明显的分化,因此分枝兔儿风被处理成宽叶兔儿风的异名。

Morphological variation of inflorescence paraclades of Ainsliaea latifolia and taxonomic status of A. Latifolia var. ramifera

The paraclade of the inflorescence of Ainsliaea latifolia was usually described as a cluster of one or 2-4 capitula without indicating its morphological nature. Extensive field and herbarium observations were conducted to examine the morphological nature and variation of paraclades in populations of A. latifolia. Three types of inflorescences can be distinguished according to the condition of reduction and condensation of the paraclades, which are simple compound cyme, complex compound cyme and the transitional type. Individuals with the last two types are rare in populations. This finding provides new insights into evolution of the various kinds of inflorescences in the genus, as well as taxonomy of this widely distributed species. The apexes of whole inflorescence axes of some individuals with complex compound cymes are broken, caused by insect eating or other external forces. It is noteworthy that the holotype of A. Iatifolia var. ramifera exhibits this phenomenon. Therefore A. latifolia var. ramifera is reduced to synonymy with the typical variety, as no other apparent difference in distribution, habitat and phenology is found between them.