61. Neohymenopogon Bennet, Indian Forester. 107: 436. 1981.
石丁香属 shi ding xiang shu
Authors: Tao Chen & Charlotte M. Taylor
Hymenopogon Wallich in Roxburgh, Fl. Ind. 2: 156. 1824, not Hymenopogum P. Beauvois (1804) [Musci].
Shrubs, usually epiphytic, unarmed, often deciduous, often rather succulent. Raphides presumably absent. Leaves opposite, apparently without domatia; stipules persistent, interpetiolar or shortly united around stem, generally ovate, acute to rounded. Inflorescences terminal, corymbose-cymose, many flowered, pedunculate, bracteate; bracts subtending 2 or more cymes per inflorescence enlarged, petaloid, stipitate (i.e., similar to a calycophyll). Flowers pedicellate, bisexual, monomorphic. Calyx limb 5-lobed. Corolla white to pale green, salverform or salverform-funnelform with tube prolonged, inside reflexed villous in throat and on lobes; lobes 5, valvate in bud. Stamens 5, inserted below corolla throat, included; filaments short; anthers dorsifixed, shortly bifid at base. Ovary 2-celled, ovules numerous in each cell on peltate axile placentas; stigmas 2, linear, partially exserted to included. Fruit capsular, oblong-ellipsoid, obovoid, or turbinate, apically prolonged into short beak, septicidally dehiscent through beak or sometimes splitting deeply into 2 valves, papery to slightly woody, with calyx limb persistent; seeds numerous, medium-sized, fusiform, acute to caudate at each end, with hilum lateral; testa membranous; endosperm rich; embryo minute; cotyledon ovate; radicle short.
About three species: Bhutan, China, India, Myanmar, Nepal, Thailand, Vietnam; two species (one endemic) in China.
The lack of raphides has not been specifically noted but is presumed here based on the classification of this genus in Cinchoneae in FRPS (71(1): x. 1999). The enlarged petaloid bracts of the inflorescences resemble the calycophylls of many other Rubiaceae species, but in Neohymenopogon many of these structures are inserted below the base of the hypanthium and are thus actually considered bracts. Puff et al. (Rubiaceae of Thailand, 172. 2005) noted that N. parasiticus grows in a variety of seasonal to evergreen epiphytic and epilithic [micro]habitats, that, not surprisingly, it is very variable morphologically, probably in correlation with habitat, and that the petaloid bracts persist on the fruit and appear to function in seed dispersal as well as in pollination. The length of the corollas of N. parasiticus for example is notably variable, by 300%, but there seems to be continuous variation and no clearly separable subgroups. Raizada and Bennet (Indian Forester 107: 432-437. 1981) noted that the name Hymenopogon, long used for these plants, was a later homonym of a moss genus and published a new name for the genus; their article contained no information about the plants apart from a summary of general geographic ranges, which were not entirely correct even then. The specific epithets of these species have sometimes been spelled as "parasiticum" and "oligocarpum," but the "-us" ending is correct (Vienna Code, Art. 62.2(a)).