The taxonomic position of Dunnia (Rubiaceae)
Dunnia, an apparently rarely collected genus of the Rubiaceae, has always been considered to be a member of the tribe Cinchoneae where, on account of the pale floral bracts, it has been compared and contrasted with Emmenopterys. On examination of the type ( Dunn’s Collector in Herb. Hongkong 910, K) it was found that raphides were abundant in all the tissues, a feature which excludes it from the Cinchoneae. The genus must belong to one of the tribes of the subfamily Rubioideae. The relevant characters at tribal level are: ovary 2-loculed with large placentas centrally attached to the septum, numerous ovules per locule; fruit a dry capsule with a hard endocarp. These characters are typical of the tribe Hedyoticleae s.l. The general appearance of the plant immediately brings to mind the genus Hymenopogon. Dunnia differs from Hymenopogon in the shape of corolla, the form and mode of dehiscence of the fruit, and in the shape of the seeds. Examination of other material of Hymenopogon revealed that the shape of the corolla and the form of the immature seeds of Hymenopogon assamicus Hook. f. deviate considerably from the type species of that genus and agree with the characters of Dunnia, where it is here placed. No representatives of Dunnia have yet been seen from Burma where the genus may also be expected to occur.
|Journal||Blumea: Biodiversity, Evolution and Biogeography of Plants|
|Rights||Released under the CC-BY 4.0 ("Attribution") License|
Ridsdale, C.E. (1978). The taxonomic position of Dunnia (Rubiaceae). Blumea: Biodiversity, Evolution and Biogeography of Plants, 24(2), 367–368.