国产耳草属长节耳草及其相似种的分类研究

Taxonomic Clarification of Hedyotis uncinella and Its Morphologically Similar Species (Rubiaceae) in China

摘要:

我国耳草属中具有茎四棱和头状花序特征的植物常常被鉴定为长节耳草(Hedyotis uncinella)，并且这一名称还包括了基于不同模式的3个分类学异名。由于这一类植物在叶片形态、叶柄长短、花序着生式样以及花梗长度等形态特征方面存在着明显的不同，因此将这一类植物笼统地鉴定为长节耳草并不合理。为清晰区分这类植物，通过模式比对、居群形态特征变异式样的野外观察以及分子系统学分析等方法进行研究，结果表明，以前被鉴定为“长节耳草”的植物实际上包括了6个分类实体，即被归并的丰花耳草(H. borrerioides)、垦丁耳草(H. kuraruensis)和新组合种——团花耳草(H. cephalophora)均应独立成种，而长节耳草本种、被忽略的线叶耳草(H. linearifolia)和我国新记录种——球花耳草(H. multiglomerulata)各自也应得到承认。同时，为了便于进行分类鉴定，也提供了这些种类的分种检索表。

Abstract:

Historically, the Hedyotis species with tetragonal stems and capitated inflorescences in China have often been identified as H. uncinella, and this name also included three heterotypic names synonymized by different taxonomists. Because this group of plants has many differences in leaf morphology, petiole length, inflorescence and pedicel length, etc., it seems to be unreasonable to lump them together into one species generally. Based on morphological comparison on type materials, field observation to morphological variation pattern in populations, and molecular phylogenetic analysis, the plants previously misidentified as H. uncinella include six taxonomic entities. Of which, H. borrerioides, H. cephalophora and H. kuraruensis should be reinstated, and the historically misidentified species of H. uncinella, the continuously overlooked species of H. linearifolia, as well as the newly recorded species of H. multiglomerulata are taxonomically distinct taxa. A key to classify these morphologically similar taxa is provided to facilitate taxonomic identification.