Oedina Tiegh.

Flora Zambesiaca. Vol. 9, Part 3. Polygonaceae-Myriaceae. Pope GV, Polhill RM, Martins ES. 2006.

Morphology Reproductive morphology Flowers Gynoecium Style

Style filiform; stigma ovoid to fusiform

Note

Danser, loc. cit. (1933) placed O. erecta (Engl.) Tiegh. (from Tanzania), O. pendens and Erianthemum virescens in Dendrophthoë, A genus of about 30 species from India to Australia, emphasizing the common features of flowers arranged in spikes or racemes. Balle, loc. cit. (1954) segregated O. pendens to a new genus Botryoloranthus because the filaments coil at anthesis like the majority of African Loranthaceae, rather than remaining erect or slightly spreading as in Asiatic genera. She retained O. erecta in Dendrophthoë following previous authors who had regarded the filaments there as erect. Additional material and our own field observations now show that the pollination mechanism is essentially the same in the two species. The flowers are opened by probing vents above a relatively short corolla tube, the lobes in O. erecta remaining erect (often somewhat coherent on the side opposite to that opened) to somewhat spreading, in O. pendens coiling and mostly breaking off. The weakly explosive opening propels pollen in one direction towards the pollinator and the slightly thicker upper part of the filaments coil, collapse and mostly detach. The species of Dendrophthoë in Asia all have relatively short filaments inserted nearer the base of the corolla lobes and remain erect; the corolla is opened variously at vents or by pinching the tip of the mature bud. The distinctions from Oncella are slight (see below). The technical distinctions between Oedina and Erianthemum are also somewhat tenuous. Danser included E. virescens in Dendrophthoë because the inflorescence is racemose, despite the very different appearance of the flowers compared to O. erecta. Species discovered in the last half century blur the differences further. On annotations of herbarium specimens in 1982 Balle has suggested that Oedina and Oncella should be combined with Erianthemum. It would seem that a number of features developed in the early radiation of the group in Africa, giving a wide range of appearance without sharp disjunction in combined characters. Nonetheless the more strongly explosive hirsute flowers of Erianthemum and their usual arrangement in heads suffices for practical separation for the present. The species of Erianthemum form a much more cohesive group than Oedina and are readily recognized. Oedina is closely allied to Asian genera and is relatively unspecialized among the African representatives. The few species have rather restricted distributions in the montane forests from Tanzania to northern Malawi, and are only locally common. The species are quite diverse in a number of features that become stabilized in more advanced genera and the limits between Oedina, Oncella and Erianthemum remain somewhat problematical.

Distribution

4 species in Tanzania and Malawi

Morphology General Habit

Shrubs extending to 2 m or more from a single haustorial attachment; hairs stellate and dendritic; twigs slightly compressed to angular, soon terete. Shrubs extending to 2 m or more from a single haustorial attachment; hairs stellate and dendritic; twigs slightly compressed to angular, soon terete

Morphology Leaves

Leaves mostly opposite or subopposite, rarely clustered, shortly petiolate, penninerved. Leaves mostly opposite or subopposite, rarely clustered, shortly petiolate, penninerved

Morphology Reproductive morphology Flowers

Flowers in racemes or spikes from axils and older nodes, few–many-flowered; bract small, unilateral. Flowers in racemes or spikes from axils and older nodes, few–many-flowered; bract small, unilateral

Morphology Reproductive morphology Flowers Calyx

Calyx saucer-shaped to tubular, entire to shortly toothed. Calyx saucer-shaped to tubular, entire to shortly toothed

Morphology Reproductive morphology Flowers Corolla

Corolla joined up to halfway, 5-lobed, radially symmetrical to slightly zygomorphic, yellow to red without any marked colour-banding, puberulous to hirsute, weakly explosive at anthesis; buds opening first by vents below middle, only slightly expanded over the anthers; tube with a slight to marked basal swelling, sometimes with a short V-slit at anthesis; lobes usually erect, often partly cohering at tips, some or all sometimes spreading to slightly reflexed from near point of filament insertion, occasionally coiled and tending to break off. Corolla joined up to halfway, 5-lobed, radially symmetrical to slightly zygomorphic, yellow to red without any marked colour-banding, puberulous to hirsute, weakly explosive at anthesis; buds opening first by vents below middle, only slightly expanded over the anthers; tube with a slight to marked basal swelling, sometimes with a short V-slit at anthesis; lobes usually erect, often partly cohering at tips, some or all sometimes spreading to slightly reflexed from near point of filament insertion, occasionally coiled and tending to break off

Morphology Reproductive morphology Flowers Androecium Stamens

Stamen filaments attached 6–10 mm above base of corolla lobes, slender, upper part slightly thickened, ± articulate, the upper part coiling, collapsing and breaking off to various degrees; anthers basifixed, 4-thecous; connective-appendage minute to subulate. Stamen filaments attached 6–10 mm above base of corolla lobes, slender, upper part slightly thickened, ± articulate, the upper part coiling, collapsing and breaking off to various degrees; anthers basifixed, 4-thecous; connective-appendage minute to subulate

Morphology Reproductive morphology Flowers Gynoecium Pistil

Style filiform; stigma ovoid to fusiform.

Morphology Reproductive morphology Fruits

Berry, where known, blue-green, ovoid-ellipsoid to obovoid; seed orange to red. Berry, where known, blue-green, ovoid-ellipsoid to obovoid; seed orange to red.