This Tree is one of the smaller Calpurnia species. It has soft, light green imparipinnate Leaves. The small Flowers are an attractive yellow and are pea-like. The Fruit develops into a grey pod that is restricted between Seeds.
Calpurnia sericea, Calpurnia intrusa, Calpurnia mucronulata.
RSA Tree No. 219.4.
Common names: Mountain Calpurnia, Berg-geelkeur, Mountain Wild Laburnum.
Family: Fabaceae, Leguminosae (Pea, bean or legume family). After the Orchidaceae and the Asteraceae, the Fabaceae is the third largest Angiosperm (flowering plants) family with 700+ genera and close to 20 000 species. Local Tree genera include Acacia (Vauchellia, Senegalia), Albizia, Bauhinia, Bolusanthus, Burkea, Calpurnia, Colophospermum, Cyclopia, Dichrostachys, Erythrina, Erythrophleum, Faidherbia, Indigofera, Mundulea, Peltophorum, Philenoptera, Schotia and Xanthocercis. The Fabaceae are recognisable by their fruit and by their pinnately compound Leaves. Leaves may also be simple and usually have stipules – some of which may be spinescent. Leaflets are usually entire. Flowers are bisexual and bracteate. Regular flowers usually have 4-5 sepals and the same number of petals. Irregular flowers have 4-5 sepals and 5 or less petals. Stamens have anthers that have 2 pollen sacs and there are usually at least twice the number of stamens as petals – often 10. The superior Ovary has one locule that may contain 1 or more ovules. The Stigma and Style are simple. The single carpel develops into the Fruit, which is usually a pod. This pod dehisces on both sides and may break into segments. Seeds vary.
Name derivation: Calpurnia Named after Calpurnius whose poetry was considered to be an imitation of Virgil’s. Calpurnia was also the last wife of Julius Caesar. There are approximately 7 species of the Genus Calpurnia in southern Africa.
Conservation Status: L C. (Least Concern). Assessment date: 2009 (Raimondo et al.).
This Tree may reach 2m in height. It is usually a much-branched shrub. Young stems are usually hairy.
The imparipinnate (pinnately compound leaf ending in a single leaflet) Leaf is up to 15cm long. Each leaf has up to 12 pairs of often-hairy (photo 234) Leaflets and the terminal 1. These leaflets may be overlapping and are ovate to elliptic to almost round. They are up to 2,5 x 1,7cm. The Apex is tapers and is occasionally mucronate (ending abruptly with a distinct hair like tip – photo 234) or it might be rounded. The Base is round to slightly lobed. Petioles (leaf stalks) are up to 20mm long. Stipules (basal appendage of the petiole) are small. Stipels (secondary stipule situated at the base of a leaflet of a compound leaf) are absent.
The yellow to orange-yellow and typically pea-shaped Flowers develop in reasonably erect Spikes (simple indeterminate inflorescences with sessile flowers on a single unbranched stalk). Flowers are small – less than 6mm long. They are bisexual and zygomorphic (the petals of the corolla are can only be divided into equal halves in one plane). The hairy Calyx is 5-lobed, with the lobes emerging from a joined base. The 5 Petals are unequal with the uppermost Vexillum (standard petal) overhanging the 2 Wing petals and these surround the lowermost pair of joined Keel petals. There are 10 Stamens with their filaments partly fused. The Anthers are small and oblong. There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma). The superior, stalked Ovary contains several ovules. There is a single arcuate (shaped like a bow – curved) Style that ends in a single Stigma with a small head. (Dec-Jan).
The Fruit is a short flat Pod, which is 2-5cm long and restricted between seeds. The newly forming pod has the remains of the calyx at the base and ends with the remains of the style. The pod is restricted between seeds. The Seeds are ovate to oblong. (Feb-Apr).
Distribution & Ecology
This plant is more common at medium altitudes close to running water and river valley floodplains. They are found in the Eastern Cape, KwaZulu-Natal, Lesotho, Eastern Free State, KwaZulu-Natal, Gauteng and Mpumalanga.
This is an attractive garden plant, which can be propagated from seeds. It flowers best when situated in full sun.
Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.
Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.
Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.
van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.
Andrew Hankey. Help with ID.