Pseudolithos P.R.O.Bally
Named from the Greek 'pseudo', false and 'lithos', stone, for the appearance of the stems. The genus has a restricted distribution of Somalia, Oman and Yemen. Tessellation of the stem's surface is a characteristic of the genus. These plants constitute some of the most succulent species among the stapeliads. They are difficult in cultivation and are often grown on grafts with the stock usually being Ceropegia linearis. All of the species seem to benefit from extra bottom heat especially in winter.
Pseudolithos caput-viperae
From Somalia, this species, together with Pseudolithos mccoyi is one of the most difficult to keep in cultivation, particularly in the northern hemisphere were it is invariably grown grafted. As can be seen it has a different flower morphology to the other members of the genus.
One of the first Pseudolithos species to be described by P.R.O.Bally in 1965, P.cubiformis from Somalia, has the largest flowers in the genus.
Originally placed in the genus Caralluma, this species found in Somalia and Oman, together with P. caput-viperae and P. mccoyi are the only freely branching members of the genus.
A recently discovered species yet to be described, from the environs of Eyl in Somalia. The town name also appears as Eil so the plant also circulates as Pseudolithos eilensis but they are one and the same. Many consider this to be no more than a variety of Pseudolithos migiurtinus.
Although it has yet to flower in my collection, this recently described Somalian species (2002) is reputed to have the smallest flowers in the genus.
This species recently discovered, clump forming species from Oman and Yemen is closely related to P. dodsonianus. Again this species appears to be very difficult in cultivation and would undoubtedly benefit from grafting.
Probably the most popular species of the genus in cultivation, it seems to grow happily on its own roots providing care is taken with watering. There are a number of handsome mature plants of this Somalian species in collections in the UK.
Pseudolithos migiurtinus x Pseudolithos dodsoniana
Despite their obvious differences in growth form, and the fact that they do not naturally hybridise in habitat, these two species do artificially produce some interesting hybrid forms.
Quaqua N.E.Brown
Distributed in south west Namibia, Namaqualand in the Northern Cape and the Great Karoo in the Western Cape Province, the genus gets its name from the Nama word 'Kam-qua-qua for Q. hottentottorum. The plants are perennial semi shrubby stem succulents, with relatively small flowers. The stems may branch basally but do not form subterranean runners. The genus does not appear to be related to any other stapeliad genus nor will it hybridise with any other member genus. It appears to be on an evolutive level between the soft stemmed species [e.g. Caralluma] and the spiny stemmed species [e.g. Hoodia].
Quaqua arida
The densely branched, greenish purple stems of this species from the Western Cape bear insignificant small yellowish flowers.
From the western regions of the Northern Cape Province and the northern regions of the Western Cape Province the species has attractive greyish purple stems which are more deeply colored in younger growth.