Origin and Habitat: Type locality, Tanzania above Lumecha river near Lumecha Bridge, about 21 km north of Songea.
Altitude range: Around 970 metres above sea level.
Habitat and ecology: Depressions and on flat rocky outcrop.

• Raphionacme grandiflora subs. glabrescens Bullock
• Pentagonanthus grandiflorus subs. glabrescens (Bullock) Bullock

• Raphionacme grandiflora subs. glabrescens Bullock
• Pentagonanthus grandiflorus subs. glabrescens (Bullock) Bullock

• Raphionacme grandiflora N.E.Br.
• Pentagonanthus grandiflorus (N.E.Br.) Bullock

Description: Raphionacme grandifloraSN|32412]]SN|32412]] subsp. glabrescens (syn. Pentagonandus grandiflorus subsp. glabrescens) is a perennial caudiciform asclepiad with herbaceous, procumbent annual hairy stems up to about 30 cm long, arising from a swollen underground, napiform root (caudex) up to 7-5 cm. It differs from the standard Raphionacme grandifloraSN|32412]]SN|32412]] only for the mostly glabrous leaves and stems, all the other characteristics clearly show that they are conspecific. The large deep violet flowers are spectacular, the corolla persisting after flowering and the violet colour turning to bright mauve. Some plants have flowers more mauve than others.
Stem: Aerial shoot erect, solitary, rarely apically branching, herbaceous, rather pale yellowish-green.
Leaves: Shortly petiolate, arranged in an alternate or opposite position, green, rather flaccid, with rough surface, pale and glossy below, nerves sunk above, raised below.
Flowers: Calyx dull purplish-green. Corolla-tube outside green, tinged violet shading to violet at the spurs opposite calyx- lobes, lobes outside yellow-green, inside deep violet. Corona whitish, finely flecked violet, centre creamy-white.

Bibliography: Major references and further lectures
1) 1) Focke Albers, Ulrich Meve “Illustrated Handbook of Succulent Plants: Asclepiadaceae”, Volume 4 Springer Science & Business Media, 2002
2) G.A. Ellenbroek “Ecology and productivity of an African wetland system: The Kafue Flats, Zambia” Springer Science & Business Media, 06 December 2012
3) Sir William Jackson Hooker “Hooker's Icones Plantarum”, Volume 36 t. 3583 page 426 Bentham-Moxon Trustees, 1962
4) Ellert, A.F.N. “A note on Pentagonanthus grandiflorus N.E. Br. subspecies glabrescens” Bullock Excelsa 18 Page 190. 1997.
5) Venter, H.J.T. “A Taxonomic revision of Raphionacme (Apocynaceae: Periplocoideae)” South African Journal of Botany 75(2) Pages 310 - 312. (Includes a picture). 2009
6) Hyde, M.A., Wursten, B.T., Ballings, P. & Coates Palgrave, M. (2016). “Flora of Zimbabwe: Species information: Raphionacme grandiflora.”
http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=145360, retrieved 21 January 2016

Cultivation and Propagation: Raphionacme grandifloraSN|32412]]SN|32412]] subsp. glabrescens is caudiciform plant that grows well in container.
Soil: Give the plant a well drained, airy but rich growing medium which consists of non organic material such us clay, pumice, lava grit, and peat or leaf-mould.
Irrigation: It is probably a summer grower species and need a good deal of water during active growth from spring when the new leaves can be seen forming from the woody neck of the tuber and should be watered only when not dormant. In autumn the leaves begin to go yellow and drop off, so now it rests quite dry in to winter. No water should ever be allowed to stand around the roots. An error in cultivation may produce unsightly holes in the tuber.
Exposure: In cultivation the plants are usually grown in semi shade, with the tubers wholly or (preferably) partially exposed to prevent scorching and rotting of the roots.
Hardiness: It should be overwintered in the greenhouse at temperatures over 12°C (avoid letting temperatures drop lower than 5° C, but some authors suggest that it can withstand light frost down to -7º C at least for short periods if very dry, in these situations it will better resist if sheltered by the winter rains, seen that the humidity and low temperatures render it more sensitive to rottenness. Plants in containers however, suffered major leaf loss.
Maintenance: The dried annual stems need to be removed to keep a tidy appearance. Like quite small pots, repot in very later winter, early spring.
Reproduction: Can be reproduced by seeds.