''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 Corolla may refer to: *Corolla (botany), the petals of a flower, considered as a unit *Toyota Corolla, an automobile model name * Corolla (headgear), an ancient headdress in the form of a circlet or crown * ''Corolla'' (gastropod), a genus of moll ...

. 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 more than 30 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 ''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 o ...

'' (Roth) Nees * '' Petalidium bracteatum'' Oberm. – s Angola?, n & c Namibia * ''

Petalidium canescens ''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 speci ...

'' C.B. Clarke * ''

Petalidium cirrhiferum ''Petalidium'', commonly known as petal-bushes, is a genus of perennial shrubs in the Acanthaceae, 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 ...

'' S.Moore * ''

Petalidium coccineum ''Petalidium coccineum'' is a species of a fast-growing shrub that bears red flowers and smooth, white bark. This shrub may grow up to 2.5 m in height. It is native to northwestern Namibia, particularly the dry savannah of Kaokoveld and Owambolan ...

'' S.Moore – nw Namibia * ''

Petalidium crispum ''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 o ...

'' A. Meeuse ex P.G. Mey. * ''

Petalidium currorii ''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 o ...

'' S.Moore – Angola * ''

Petalidium cymbiforme ''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 o ...

'' Schinz * ''

Petalidium giessii ''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 o ...

'' P.G. Mey. * ''

Petalidium glandulosum ''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 o ...

'' S.Moore * ''

Petalidium gossweileri ''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 o ...

'' S.Moore * ''

Petalidium halimoides ''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 o ...

'' (Nees) S.Moore – Namibia * ''

Petalidium huillense ''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 o ...

'' C.B.Clarke * ''

Petalidium lanatum ''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 o ...

'' C.B. Clarke * ''

Petalidium lepidagathis ''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 o ...

'' S.Moore * ''

Petalidium linifolium ''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 o ...

'' T. Anderson * ''

Petalidium lucens ''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 o ...

'' Oberm. * ''

Petalidium luteo-album ''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 o ...

'' A. Meeuse * ''

Petalidium oblongifolium ''Petalidium'', commonly known as petal-bushes, is a genus of perennial shrubs in the Acanthaceae, 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 ...

'' C.B. Clarke – South Africa * ''

Petalidium ohopohense ''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 speci ...

'' P.G. Mey. * '' Petalidium physaloides'' S.Moore – Namibia * '' Petalidium pilosi-bracteolatum'' Merxm. & Hainz – Namibia * '' Petalidium ramulosum'' Schinz * '' Petalidium rautanenii'' Schinz * ''

Petalidium rossmannianum ''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 o ...

'' P.G. Mey. * '' Petalidium rupestre'' S.Moore * '' Petalidium setosum'' C.B. Clarke ex Schinz – n, c & s Namibia * ''

Petalidium spiniferum ''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 o ...

'' C.B.Clarke – Chella Mountains, Angola * ''

Petalidium subcrispum ''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 o ...

'' P.G. Mey. * ''

Petalidium tomentosum ''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 o ...

'' S.Moore * '' Petalidium variabile'' C. B. Cl. Hybrid * ''

Petalidium welwitschii ''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 o ...

'' S.Moore

References

External links

Petalidium Nees
Flora of Tropical Africa, Kew, Global Plants * {{Taxonbar, from=Q10348914 Acanthaceae genera