10. Caelospermum Blume, Bijdr. 994. 1826.
穴果木属 xue guo mu shu
Authors: Tao Chen & Charlotte M. Taylor
Lianas or sometimes shrubs or small trees, unarmed. Raphides present. Leaves opposite or rarely ternate, decussate on ascending branches but distichous on horizontal branches, with domatia; stipules persistent at least on apical 2 or 3 nodes and usually becoming hardened with age, at least shortly united around stem [or rarely interpetiolar], triangular and acute to truncate, sometimes shortly 2-toothed. Inflorescences terminal and sometimes in axils of uppermost leaves, corymbiform to paniculiform with flowers grouped in small heads or umbelliform cymes, many flowered, pedunculate, bracteate or bracts reduced. Flowers pedicellate to sessile, free [sometimes fused by their ovaries], bisexual, apparently monomorphic. Calyx with ovary portion usually hemispherical or campanulate; limb tubular, truncate or 4-6-denticulate. Corolla white becoming yellowed when old, salverform or funnelform, fleshy, variously pubescent inside; lobes 4 or 5(or 6), valvate in bud. Stamens 4 or 5(or 6), inserted in corolla tube, exserted; filaments developed; anthers dorsifixed near middle, 2-parted at base. Ovary 2-celled with ovules 2 in each cell or 4-celled via secondarily developing septa and ovules 1 in each cell, ovules inserted on middle of septum, anatropous or pendulous; stigmas 2, linear to spatulate, exserted or included. Fruit simple [sometimes multiple due to fusion of flowers], dark red to dark purple, drupaceous, fleshy, subglobose to ellipsoid, smooth, with calyx limb persistent; pyrenes 2, 3, or usually 4, 1-celled with 1 seed in each cell, ellipsoid to plano-convex, cartilaginous, densely puberulent; seeds medium-sized; endosperm oily; embryo straight.
Seven to ten species: from tropical Asia to Australia; one species in China.
This genus is similar and has long been considered related to Morinda and perhaps will be synonymized eventually, but it has provisionally been maintained by recent workers (Razafimandimbison et al., Molec. Phylogen. Evol. 48: 207-223. 2008). This genus was studied by Johansson (Blumea 3: 265-297. 1988), who synonymized the two species recognized by Y. Z. Ruan (in FRPS 71(2): 166-167. 1999) in China together with several other SE Asian names into a wide-ranging, morphologically variable species with the variation apparently continuous.