圓萼牽牛（旋花科）在亞洲之鑑定

The Identity of Ipomoea staphylina (Convolvulaceae) in Asia

一百七十五年來，熱帶亞洲地區都以Ipomoea staphylina為圓萼牽牛及其相似種類之學名。根據臘葉標本及活植物之觀察研究，證實I. staphylina包括三種不同植物。問題之產生可追溯到1930年代，Merremia boisiana之標本被鑑定成Ipomoea staphylina，而且其中包含二相似種。本文討論相似種間之命名問題，同時對每一學名都列有模式標本。為鑑定方便起見，亦提供相關種類之檢索表，及主要區分特徵之圖鑑；同時提供圓萼牽牛（Ipomoea staphylina）及蘇門答臘牽牛（I. sumatrana）兩種之異名、分布及標本索引。

For the last 175 years the name Ipomoea staphylina has been applied throughout much of tropical Asia to one of the few lianoid species of Ipomoea found there. Study of herbarium specimens and living plants revealed that three distinct taxa are passing under the name I. staphylina. Two problems emerged: a pernicious confusion dating back to the 1930s, in which collections of Merremia boisiana (Gagnepain) Ooststroom were misidentified as I. staphylina, and, a taxonomic problem that requires delimitation of two similar species of Ipomoea, both heretofore called I. staphylina. The nomenclature is discussed for names pertinent to this taxonomic problem and all names are typified. A key to the three similar taxa and an illustration of their diagnostic characters are provided to aid in recognizing them. The synonymy and geographic distribution are summarized for the two species of Ipomoea and an index of numbered collections examined is provided.