Osmophore structure and phylogeny of C irrhaea ( O rchidaceae, S tanhopeinae)

Phylogenetic relationships and osmophore evolution of six C irrhaea spp. were studied. Floral morphology was analysed using fresh flowers, and osmophore anatomy was determined on the basis of fixed flowers. Phylogenetic relationships of C irrhaea were inferred on the basis of internal transcribed spacer ( ITS ), mat K and trn L ‐ F regions using maximum parsimony and Bayesian analyses. Floral morphology and osmophore structure vary among species. All C irrhaea osmophores have a secretory epidermis without papillae. C irrhaea is monophyletic and includes three subclades: (1) C . dependens / C . nasuta , with a secretory cylindrical protuberance at the base of the labellar midlobe; (2) C . fuscolutea / C . longiracemosa , with a secretory tissue at the base of the shell‐shaped midlobe; and (3) C . loddigesii / C . seidelii with secretory tissue on the inner surface of the lateral lobes. The features of the flowers and osmophores in C irrhaea spp. extend our knowledge of the diversity of secretory structures in S tanhopeinae, and demonstrate that floral morphology reflects phylogenetic relationships in Cirrhaea . © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society , 2014, 176 , 369–383.