Raphionacme Harvey
Derived from the Greek words 'rhaphys', beet-root, and 'akme' sharpness, presumably describing the taste of the tuberous roots. The genus is found in Oman in the north and south through many other tropical and sub-tropical areas of the African continent. It consists of small growing erect and rarely climbing geophytes of the sub family Periplocoidae. In cultivation the plants are usually grown in semi shade, with the tubers wholly or partially exposed to prevent scorching and rotting of the roots.
Raphionacme angolensis
As the name indicates the species is found principally in Angola, but also in neighbouring Tanzania, where the plant shown originates. The turnip shaped tuber bears shrubby stems to 60cm and characteristic heads of flowers. The species is very closely related to R. procumbens with which it may actually be conspecific.
Found in the Northern provinces of South Africa, Namibia and Botswana, this species is closely related to R. galpinii, R. velutina and R. zeyheri.
From the Eastern Cape, KwaZulu-Natal and Mpumalanga, the flower colour varies geographically - the plant pictured is from Mpumalanga whilst those from the Eastern Cape have dark green flowers and those from KZN, pale green pubescent flowers.
A very widespread and variable species coming from Angola, the Eastern and Northern Provinces of South Africa, Swaziland, Tanzania, Zaire, Zambia, and Zimbabwe
Until recently in the genus Pentagonanthus, this species has now been placed in Raphionacme, where its spectacular large violet blue flowers rightly earn it the name grandiflora. It is to be found in dry forests and on rocky outcrops in Tanzania, Zambia, Malawi, Zimbabwe and Mozambique. The plant shown comes from the Ruvuma province of Tanzania.
Another widespread species found in Ivory Coast, Malawi, Zambia, Zimbabwe and more recently in the Morogoro Province of Tanzania from whence the plant pictured was found.
This short grassland species with a short free standing stem can be found in Tanzania Zambia, Malawi and northern Zimbabwe. The plant shown here is from the Mbeya Province of Tanzania and was originally named Raphionacme ernstiana but this species has recently been sunk into R. longituba.
Another short stemmed species with attractive flowers, Raphionacme madiensis comes from the woodlands and grasslands of Uganda, Kenya and Tanzania. The plant pictured is from the Ruvuma Province of Tanzania.
Rhytidocaulon Bally
From the Greek 'rhytidos', wrinkle or fold, and 'kaulos', stem for the sculptured appearance of the stems. The plants are little-branched perennial stem succulents, closely related to the genus Caralluma with a distribution area of Ethiopia, Kenya, Somalia, Oman, Saudi Arabia and Yemen, which is totally within the growing are of Caralluma. However they differ from all other stapeliads in their wrinkled rough irregular stems which are covered in a waxy layer, which is most conspicuous when the plants are in full growth, and in their inflorescences which are sunken into the stems. They seem to benefit from a little extra warmth and seem to do better in semi shade, as in habitat they are usually found growing under bushes. The genus is difficult in cultivation and may be better grown grafted although I have not seen this done as yet in the UK.
Only described in June 2006, this species is aptly named for the web threads found on the surface of the corolla.
A distinctive species with small cage like flowers found only in Oman
Rhytidocaulon macrolobum ssp macrolobum
Found in Saudi Arabia, Somalia, and Yemen, the flower colour and banding are variable as can be seen from the plants shown here, the background colour of the corolla is normally black but there are clones with a dark olive green, and rarely a maroon coloured corolla.
Rhytidocaulon macrolobum ssp minimum
With smaller unscented flowers this species is native to Saudi Arabia and Yemen.
This rare species is known from only three localities, one each in Ethiopia, Kenya and Somalia.
Found only in Saudi Arabia and named after Sheila Collenette who is well known for having botanised widely in that country. Species aff. sheilae RH902 is a Ricanek and Hanachek collection from Wadi Dhar, Yemen.
Closely related to R. sheilae but found in Ethiopia and Somalia