- Source: Petalidium
Petalidium, commonly known as petal-bushes, is a genus of perennial shrubs in the acanthus family. They are native to sandy flats or stony slopes in the drier bush regions of Africa, India and the Mascarene Islands. The majority of species occur in frost-free, summer rainfall regions of southern Africa, and may be found from low to medium altitudes.
Description
They have a diverse habit, forming either small, scrambling herbs or large, robust shrubs. Their dilated, tubular flowers are solitary or on short racemes growing from the leaf axils, and vary from white to mauve or red in colour. The four stamens are partially fused with the corolla, and the style is branched into two unequal parts. The calyx is deeply divided into five segments.
Two large, ovate to elliptic bracteoles subtend and protect the young corolla. The persistent bracteoles may be conspicuously veined or covered by long, villous trichomes. The small, ellipsoid fruit capsules explosively release two to four flat seeds (two ovules per ovary cell) when moisture is absorbed by their hygroscopic hairs. Young foliage and branches are covered in gland-tipped hairs. The leaves are entire.
Cultivation
Some species are cultivated as ornamentals, as they grow fast and flower profusely.
Etymology
According to Jackson (1990), the name Petalidium is derived from the Greek petalon (a leaf or petal), which may refer to the deciduous, leaf-like bracts, while bracteatum likewise refers to the large, imbricate (i.e. overlapping) bracts.
Species
There are 41 species in all, of which 29 occur in southern Africa. The species include:
Petalidium angustitubum P.G.Mey.
Petalidium aromaticum Oberm. – n South Africa, s Zimbabwe
Petalidium barlerioides (Roth) Nees
Petalidium bracteatum Oberm. – s Angola?, n & c Namibia
Petalidium canescens (Engl.) C.B.Clarke
Petalidium cirrhiferum S.Moore
Petalidium coccineum S.Moore – nw Namibia
Petalidium crispum A. Meeuse ex P.G. Mey.
Petalidium currorii S.Moore – Angola
Petalidium cymbiforme Schinz
Petalidium elatum Benoist
Petalidium englerianum (Schinz) C.B.Clarke
Petalidium giessii P.G.Mey.
Petalidium glandulosum S.Moore
Petalidium gossweileri S.Moore
Petalidium halimoides (Nees) S.Moore – Namibia
Petalidium huillense C.B.Clarke
Petalidium kaokoense Swanepoel – Namibia
Petalidium lanatum C.B.Clarke
Petalidium lepidagathis S.Moore
Petalidium linifolium T.Anderson
Petalidium lucens Oberm.
Petalidium luteoalbum A.Meeuse
Petalidium mannheimerae Swanepoel, Nanyeni & A.E.van Wyk
Petalidium microtrichum Benoist
Petalidium oblongifolium C.B.Clarke – South Africa
Petalidium ohopohense P.G.Mey.
Petalidium parvifolium Schinz
Petalidium physaloides S.Moore – Namibia
Petalidium pilosibracteolatum Merxm. & Hainz – Namibia
Petalidium ramulosum Schinz
Petalidium rautanenii Schinz
Petalidium rossmannianum P.G.Mey.
Petalidium rupestre S.Moore
Petalidium setosum C.B.Clarke ex Schinz – n, c & s Namibia
Petalidium spiniferum C.B.Clarke – Chella Mountains, Angola
Petalidium subcrispum P.G.Mey.
Petalidium tomentosum S.Moore
Petalidium variabile (Engl.) C.B.Clarke
Petalidium welwitschii S.Moore
References
External links
Petalidium Nees, Flora of Tropical Africa, Kew, Global Plants