In the subfamily Metastelminae the genus is thought to be named for Philibert Commerson, an 18th century French botanist, doctor, and explorer.
Philibertia gilliesii var gracilis is a climbing perennial from Argentina, whose flowers smell vaguely of tomatoes. The plant pictured was grown from IAS 1467 seed.
Named from the Greek 'piar', fat, and 'anthos', flower, referring to the fleshy corolla. Vegetatively Piaranthus is indistinguishable from Duvalia when not in flower. This is due to their having the same habitat preferences, both being mat forming under host plants. For this reason in cultivation they are probably best grown in partial shade. To me this appears to be a very poorly understood and confusing genus subject to constant revision by various authors.
As the name implies this species comes from around the town of Barrydale in the Little Karoo region of the Western Cape Province. It is closely allied to the P. geminatus/P. foetidus complex.
With globose, cylindrical, slightly rough stems, this very variable species is to be found in the Western, Eastern and Northern Cape Provinces.
This sub species prefers the more arid regions of southern Namibia and the Namaqualand region of the Northern Cape. Although not naturally hybridising, the genus Piaranthus can produce some interesting hybrids in cultivation.
This species prefers a higher altitude being found in the Northern and Western Cape Provinces in Mountain Karoo to a height of 1300m.
From the same mountain Karoo area as P. decorus ssp. decorus at between 500-1100m, P. framesii has characteristically bell shaped flowers, and unlike the closely related Piaranthus punctatus has papillae on the corona instead of hairs. The plant shown, CM0006 was collected at Gannabos, off the R355, SE of Loriesfontein, in August 2000.