Wood anatomy of the subfamily Crotonoideae (Euphorbiaceae s.s.) from India: systematic implications with special reference to the taxonomic delimitation of Givotia and Vernicia Prem Prakash Jangid and Sangeeta Gupta P. P. Jangid (ppjangid2010@gmail.com) and S. Gupta, Wood Anatomy Discipline, Botany Division, Forest Research Inst., IN-248006 Dehradun, India. Te wood anatomy of 15 representative species belonging to 12 genera of nine tribes of the subfamily Crotonoideae (Euphorbiaceae) are comprehensively described with focus on systematic implications. In addition, ecological and evo- lutionary aspects are evaluated. An identification key to the species based on wood anatomical features is presented. Te wood microstructure of the tribes was found to be considerably heterogeneous reflecting an unnatural classification of the subfamily. However, the results confirm the generic relationship within subtribe Aleuritinae and tribe Ricinodendreae. Vernicia and Givotia may be recognized based on wood anatomical and morphological characters. Te tribes Micrandreae and Adenoclineae have considerable similarity in wood anatomy. Te wood structure of the monogeneric tribes Trigonos- temoneae and Geloneae idicate a close relationship with the tribe Crotoneae. Te pantropical subfamily Crotonoideae is one of three subfamilies of the spurge family Euphorbiaceae s.s . Te subfamily include notable economic products such as cassava ( Manihot esculenta), rubber ( Hevea brasiliensis) and tung oils ( Vernicia spp.), as well as many medicinal plants (Balakrishnan and Chakrabarty 2007). Crotonoideae is traditionally circumscribed to contain laticiferous taxa with crotonoid pollen. Morphology-based classifications for the subfamily have been proposed by Müller (1866), Bentham (1880), Pax (1890), Hurusawa (1954), Hutchinson (1969), Webster (1975, 1994) and Radcliffe-Smith (2001). Webster (1994) recognised 12 tribes and 68 genera in Crotonoideae. Te classification of Radcliffe-Smith (2001) was almost identical to that of Webster (1994) as far as the composition of Crotonoideae is concerned (12 tribes, 74 genera). Wurdack et al. (2005) stud- ied the molecular phylogeny of this subfamily and divided it into four clades, viz Adenoclineae, Geloneae, ‘articulated crotonoids’ and ‘inaperaturate crotonoids’. Systematic and phylogenetic palynological studies have been important as guides of the current classifications (Erdtman 1952, Punt 1962, Webster and Rupert 1973, Nowicke 1994, Lobreau- Callen and Sua´Rez-Cervera 1997, Tokuoka and Tobe 1998, Lobreau-Callen et al. 2001). Prior to the current definition of Euphorbiaceae, Hayden and Hayden (2000) and Mennega (2005) briefly compared the wood structure of Crotonoideae with the uni-ovulate subfamilies Acalyphoideae and Euphorbioideae, and also with what was then recognized as the bi-ovulate subfami- lies Phyllanthoideae and Oldfieldioideae. Tese latter sub- families are now roughly equivalent to Phyllanthaceae and Picrodentraceae. From an Indian perspective, an overview of gross wood structure of the subfamily has been provided by Gamble (1922), Pearson and Brown (1932), Metcalfe and Chalk (1950) and Raturi et al. (2001). Rudall (1994) studied the homology and evolution of laticifers in Croto- noideae. Weidenhoeft et al. (2008) studied the phylogeny by wood anatomy of tribe Crotoneae. Although several wood anatomical studies have been done on Euphorbiaceae, the wood anatomy in particular of subfamily Crotonoideae and its systematic implication has not yet been studied in detail. Te systematics of Crotonoideae in the present paper is based on Webster (1994). Te subfamily is represented in India by 60 species belonging to 16 genera and 10 tribes (Balakrishnan and Chakrabarty 2007). Te present paper deals with the wood anatomical study of 37 specimens belonging to 15 representative species of 12 genera covering 9 tribes of the subfamily. Te aims of this study was to evaluate the systematic relationships of supra-generic taxa and evaluate the morpho- logical and molecular classification of the subfamily Croto- noideae based on a wood anatomical approach. A species identification key should be developed based on wood ana- tomical characters. Also ecological and evolutionary aspects of the subfamily should be considered. As a result, we will suggest possible modest taxonomic changes at generic and © 2016 Te Authors. Nordic Journal of Botany © 2016 Nordic Society Oikos Subject Editor and Editor-in-Chief: Torbjörn Tyler. Accepted 1 January 2016 Nordic Journal of Botany 000: 001–018, 2016 doi: 10.1111/njb.00990, ISSN 1756-1051 Early View (EV): 1-EV