利用數值分類方法比較臺灣野生茶與兩近緣分類群之形態特徵關係

Morphological Comparisons of Taiwan Native Wild Tea Plant (Camellia sinensis (L.) O. Kuntze forma formosensis Kitamura) and Two Closely Related Taxa Using Numerical Methods

臺灣野生茶（Camellia sinensis f. formosensis）乃泛指自生於臺灣中海拔山區的茶類植物，臺灣植物誌將其中名稱為臺灣山茶。在分類史上，臺灣野生茶曾經被處理成數個不同分類階層的歸屬。為了提供分類學者一個更客觀的看法，我們利用數值分類方法中的群聚分析（cluster analysis）與非線性主成份分析（nonlinear principal component analysis），計算了165份標本中的16個營養及11個花部特徵的測量值，並依據分析結果來探究臺灣野生茶與關係密切的茶（C. sinensis var. sinensis）和阿薩姆茶（C. sinensis var. assamica）的區別。將營養及花部特徵獨立或合併進行群聚分析的結果幾乎一致地指出臺灣野生茶在形態特徵上的獨立性。相反地，茶與阿薩姆茶的形態差異卻無法被解析出來。非線性主成份分析則顯現休眠芽與子房的毛被狀態是區分臺灣野生茶以及茶與阿薩姆茶的最有效特徵。參照目前分類學家對茶與阿薩姆茶這兩群植物的分類處理，我們建議臺灣野生茶應該被處理成種的階層會比較恰當。

Camellia sinensis (L.) O. Kuntze forma formosensis Kitamura is generally referred to as the tea plant growing naturally in mid-elevation mountains of Taiwan. Several taxonomic treatments have been published for this plant in the past, but some contradictory results have been obtained. To assess the taxonomic position of the wild tea plant and explore its relationship with two other closely related taxa, C. sinensis var. sinensis and C. sinensis var. assamica, 16 vegetative and 11 floral characters were examined on 165 OTUs. The data were analyzed using cluster analysis and nonlinear principal components analysis. All cluster phenograms consistently separated the native wild tea plant from two other related taxa. Conversely, pronounced admixture between C. sinensis var. sinensis and C. sinensis var. assamica was present. The nonlinear principal components analysis indicated that the surface features of buds and ovaries are two diagnostic characters. Based on the present study, it is proposed that the Taiwan native wild tea plant might deserve recognition as a distinct species.