Morphometric analysis of the Taxus wallichiana complex (Taxaceae) based on herbarium material MICHAEL MÖLLER 1 *†, LIAN-MING GAO 2 †, ROBERT R. MILL 1 , DE-ZHU LI 2 , MICHELLE L. HOLLINGSWORTH 1 and MARY GIBBY 1 1 Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, Scotland, UK 2 Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan, 650204, China Received July 2006; accepted for publication May 2007 We used morphological and geographical data of 128 herbarium specimens of the Taxus wallichiana complex in eastern Asia to investigate their utilization in discriminating and identifying taxa included in the complex. One bud scale and 26 leaf characters were used to separate T. fuana, T. wallichiana var. wallichiana, T. wallichiana var. mairei, T. wallichiana var. chinensis and T. sumatrana by K-means clustering and dendrograms using Ward’s distance. Out of the 27 characters examined 21 were found to be well correlated with geographical patterns. T. fuana was morphologically the most distant taxon, while T. sumatrana clustered among the T. wallichiana varieties. After correcting misidentifications of the specimens in T. wallichiana, its varieties occupied discrete geographical ranges, except for some limited sympatry of varieties mairei and chinensis east of the Tanaka– Kaiyong line and the Sichuan Basin, China. Our analysis demonstrates the importance of consistency in character selection and definition in the identification of morphologically difficult taxa and the power of combining morphometric and geographical data in clarifying their spatial distribution. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 307–335. ADDITIONAL KEYWORDS: China – geographical distribution – PCA – taxonomy – Taxus fuana – Taxus sumatrana – variety delimitation. INTRODUCTION The taxonomy of the genus Taxus L. is complex and inconsistent over large areas of its distribution range. The main problem in this genus arises from a lack of discrete (‘hard’) vegetative characters. This is aggra- vated by the fact that herbarium specimens are often sterile and so a whole suite of potentially suitable generative morphological features cannot be used. A large number of vegetative characters are hard to find and constitute mainly characters of the leaf. The majority of these are continuous and often difficult to define unequivocally. Terminological problems and interpretation of character states can further hamper taxonomic communication. Proper identification is paramount to comply with CITES regulations because all Taxus species occurring in China have been listed as first-class protected plants by the central government of China since 1999 and were listed in Appendix II of CITES since 1995 (http:// www.cites.org/eng/app/appendices.shtml#10). Taxus includes four species in North America (T. brevifolia Nutt., T. canadensis Willd., T. floridana Nutt., T. globosa Schlecht.), one in Europe and western Asia (T. baccata L.), and several in east and south-east Asia. The taxonomy of these latter taxa is still in flux. De Laubenfels (1988) included all the Chinese and Indo-Chinese yews, except for T. cuspi- data Siebold & Zucc., in T. sumatrana (Miq.) de Laub., but other authors have not taken such a broad view. Li & Fu (1997) established Taxus fuana Nan Li & R. R. Mill for specimens from Xizang (Tibet), and from central Nepal westwards to Pakistan and Afghanistan. Fu, Li & Mill (1999), while retaining T. cuspidata and T. fuana, recognized three varieties *Corresponding author. E-mail: m.moeller@rbge.org.uk †These two authors contributed equally to the study. Botanical Journal of the Linnean Society, 2007, 155, 307–335. With 9 figures © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 307–335 307 Downloaded from https://academic.oup.com/botlinnean/article/155/3/307/2420200 by guest on 18 August 2022