Otholobium virgatum (Burm.f) C.H. Stirt.
Common names: carpet pea, mat otholobium, eight-day-healing bush (Eng.); agtdaegeneesbossie (Afr.)
This is a mat-forming and low-growing, trailing, ground cover with masses of mauve-pink, pea-like flowers in spring.
Otholobium virgatum is a trailing, resprouting, hairy, frequently matted shrublet and has upright branchlets. Younger parts are white-hairy. The 6–10 mm long leaves are 3-foliolate and slightly hairy. The leaflets are inversely egg- or heart-shaped. The stipules are small, point extended and slightly hairy.
It bears masses of flowers which are produced in threes along the stems, crowded towards branchlet ends. They have short stalks. The calyx is veined, softly hairy, glandular, with 2 upper lobes partly united. The petals are pale pink to mauve–purple; keel purple-tipped. The pods of O. virgatum are 1-seeded and covered with hairs.
Otholobium virgatum is assessed as Least Concern (LC) according to the Red List of South African Plants, checked in October 2014, which means it is not threatened.
Distribution and habitat
Otholobium virgatum occurs commonly in Fynbos areas near marshes, up to 400 m altitude. It occurs from Porterville and Saldanha in the Western Cape to the Eastern Cape. The agtdaegeneesbos is adapted to sandy soil types and winter coastal rainfall and a frost free zone.
Derivation of name and historical aspects
This species was until recently known as Otholobium decumbens (Aiton) C.H.Stirt.
Fabaceae is derived from the Latin word Faba meaning ‘bean'. The older name Leguminosa e is still considered valid and it refers to the fruit of which are called legumes. The genus name Otholobium (pronounced oh-tho-LOH-bee-um) comes from the Greek words otheo meaning to ‘burst forth' and lobion meaning ‘small pod'. The specific epithet, virgatum (pronounced vir-GAY-tum) is derived from Latin meaning ‘wand-like', referring to the tall, twiggy-like bare stems.
Fabaceae is the third largest family of flowering plants after Asteraceae and Orchidaceae. The pea family occurs worldwide except in Antarctica and the high Arctic and comprises of trees which are often found in tropical regions, whereas, shrubs, perennials and annuals are predominant in extra tropical regions. The leaves of Fabaceae are mostly alternate, usually compound, sometimes needle like, often visibly stipulate. Inflorescence is usually a raceme, sometimes tightly clustered. Flowers are mostly yellow, or pink to purple, regular or irregular. They are often sweet pea-shaped, with mostly 5 sepals, and often joined into a cup; petals mostly 5, the uppermost largest and forming a flag, the lower 2 are joined into a keel hiding the stamens and style, and the laterals forming wings. Stamens are mostly twice as many as the petals, frequently united into a split tube, ovary superior, style slender, usually hooked at the tip. Fruit a pod with seeds in 1 row. The pea family comprises of 650 genera and +/-18 000 woody and herbaceous species, of which southern Africa has 149 genera and 1705 species.
Worldwide, the family supplies a number of important agricultural and food plants such as soybean, lentils, chickpeas, pea, beans, alfalfa, peanut, carob and Liquorice, forage crops like Lucerne, ornamentals, tropical hardwoods, dyes, and insecticides. A number of species are also weedy pests in different parts of the world. In our areas we have 2 weeds.
Otholobium virgatum has a pea-like flower structure adapted for pollination by insects or birds and it attracts butterflies. Most Fabaceae roots are coposed of nodules that house soil organisms which fix nitrogen from the air. This feeds the host plant and when the roots die, surplus nitrogen remains in the soil which is used by other plants. This process is called nitrogen fixation.
According to Smith (1966) Otholobium virgatum was formerly used medicinally to treat sores and various ailments, the leaves were made into a salve or brewed into a tea which was believed to heal within eight days, hence agdaegenesbossie. It shares this common name with Lobostemon fruticosus, Chironia baccifera and Hermannia hyssopifolia and H. cuneifolia.
Otholobium virgatum is used in horticulture as a groundcover.
Growing Otholobium virgatum
It is easy to grow and it requires low maintenance. It prefers sunny spot but does well in semi-shade as well. O. virgatum can be used as a ground cover, instead of a lawn in areas which take no traffic. It can also be used as outdoor pots in swimming pool areas, water-wise gardens and when landscaping for seaside gardens.
It may be grown from cuttings which should be taken early in the morning to prevent wilting. O. virgatum roots quickly and easily from cuttings taken from new growth. Keep cutting material moist throughout. Treat with rooting hormone before placing them in growing media. It should take 2–4 weeks before they are rooted.
- Manning, J. 2007. Field guide to Fynbos. Struik Publishers, Cape Town.
- Manning, J.C. & Goldblatt, P. 2013. Plants of the Greater Cape Floristic Region. 1: The Core Cape Flora. Strelitzia 29. South African National Biodiversity Institue, Pretoria.
- Trinder-Smith, T. 2006. Wild flowers of Table Mountain. Botanical Society of South Africa, Cape Town
- Dave's Garden. http://davesgarden.com/guides/botanary/go/18893/#b . Accessed 28/10/2014
- Latin and Greek Meanings and Derivations. http://www.calflora.net/botanicalnames/pageV.html. Accessed 28/10/2014
- Wikipedia The Free Encyclopedia. http://en.wikipedia.org/wiki/Fabaceae . Accessed 28/10/2014
- Smith, C.A. 1966. Common names of South African plants. Memoirs of the Botanical Survey of South Africa No. 35. Government Printer, Pretoria.
Kirstenbosch National Botanical Garden
Plant Type: Ground Cover, Shrub
SA Distribution: Eastern Cape, Western Cape
Soil type: Sandy, Loam
Flowering season: Spring
Flower colour: Pink, Mauve/Lilac
Aspect: Full Sun
Gardening skill: Easy