Oncosiphon suffruticosum is an aromatic annual with masses of bright yellow flower heads, and is an important Cape herbal medicine.
Oncosiphon suffruticosum is a strongly aromatic annual herb up to 50 cm tall. Leaves finely divided, pinnatisect (divided feather-like to the midrib), glabrous.
Flower heads 4–6 mm diam., yellow, lacking ray florets, arranged in dense corymbs (± flat-topped inflorescences in which the branches all reach to about the same level), involucral bracts (surrounding the flower heads) ± glabrous. Florets bisexual, 4-lobed, with a thickened floral tube. Flowering time: September–December.
Fruits small, brownish, 4-ribbed, crowned with a small unequal-sided pappus of white scales, non-myxogenic (not forming mucus when wetted).
Least Concern ( Raimondo et al . 2009 ).
Distribution and habitat
Oncosiphon suffruticosum is a widespread species endemic to the Greater Cape Floristic Region where it occurs in sandy, often coastal soils, from southern Namibia south to Gansbaai in the Western Cape Province (Goldblatt & Manning 2000). In disturbed veld it is often abundant. It has become a weed in southern Australia and parts of the USA.
Derivation of name and historical aspects
The generic name, Oncosiphon, is derived from the Greek word oncos, meaning thick, swollen, and siphon, meaning tube, and refers to the conspicuously swollen corolla tube characteristic for the genus ( Källersjö 1988). The specific epithet, suffruticosum, combines the Latin prefix sub - ( suf -) meaning somewhat, and fruticosum, shrubby, and refers to the shrublet-like habit of this species.
Oncosiphon suffruticosum is a common weed in the Western Australian wheatbelt ( Borger 2008 ) where it is known as Calomba daisy, referring to the place in southern Australia where the plant was first collected. It is thought to have been imported into Australia during the drought of 1922 as part of a fodder consignment from South Africa (Parsons & Cuthbertson 2001).
The plants are annuals that germinate with the onset of the winter rains and flower during late spring. In their native range they form part of the spectacular spring floral displays for which the region is renowned. The fruit of the closely related genera Foveolina and Pentzia have specialized slime-producing cells called myxogenic cells which rupture when they come into contact with water, releasing mucilage or slime which aids in the absorption and retention of water for germination. However, in Oncosiphon these cells are conspicuously absent.
Uses and cultural aspects
An important Khoi-San remedy still utilized today. Oncosiphon suffruticosum is included in the Cape herbal medicine materia medica of Van Wyk (2008). An infusion of the entire plant is taken orally to treat stomach pain, colds and influenza, intestinal worms, typhoid fever, rheumatic fever, pneumonia, asthma, and as a digestive tonic (Van Wyk et al . 2009 and references therein). A small quantity of the juice squeezed from fresh leaves is added to mother's milk to treat infants suffering from winds and cramps (Van Wyk & Gericke 2000). A poultice of the leaves is also applied topically for inflammation and scorpion stings (Van Wyk et al . 2009 and references therein).
Growing Oncosiphon suffruticosum
Oncosiphon suffruticosum is easily propagated by seed sown in autumn (March) . The species is ideal for coastal gardens and should be planted in full sun. Plants tend to become somewhat scraggly and are best planted together en masse with other spring flowering species, e.g. Arctotis spp. , Dimorphotheca sinuata (Namaqualand daisy), D. pluvialis , Felicia spp., Heliophila coronopifolia , Senecio elegans , Ursinia calendulifolia , U. cakilefolia and U. speciosa .
References and further reading [
- Borger, C. 2008. Matricaria and Calomba daisy. E-weed 9(9): 1-8. http://www.agric.wa.gov.au/objtwr/imported_assets/content/pw/e-weed_9_december_2008.pdf.
- Goldblatt, P. & Manning, J.C. 2000. Cape plants . A conspectus of the Cape flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.
- Källersjö, M. 1988. A generic reclassification of Pentzia Thunb. (Compositae–Anthemideae) from South Africa. Botanical Journal of the Linnean Society 96: 299–322.
- Parsons, W.T. & Cuthbertson, E.G. 2001. Noxious weeds of Australia . CSIRO Publishing.
- Raimondo, D., Von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. & Manyama, P.A. 2009. Red List of South African plants 2009. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
- Smith, C.A. 1966. Common names of South African plants. Memoirs of the Botanical Survey of South Africa No. 35.
- Van Wyk, B.-E. & Gericke, N. 2000. People's plants: A guide to the useful plants of southern Africa . Briza Publications, Pretoria.
- Van Wyk, B.-E. 2008. A review of Khoi-San and Cape Dutch medical ethnobotany. Journal of Ethnopharmacology 119: 331–341.
- Van Wyk, B.-E., Van Oudtshoorn, B. & Gericke, N. 2009. Medicinal plants of South Africa . Briza Publications, Pretoria.
Anthony R Magee