Most farmers are familiar with the important legumes that are cultivated for food and pasture production. Lucerne, clover, medics, vetch, lupins, cowpeas, soya beans, groundnuts, field beans and peas are all crops that we depend on for livestock and human food production.
What is perhaps less known is that they all belong to the third-largest flowering-plant family in the world, the and there are many hundreds of species that grow wild in South Africa in virtually every habitat and veld type.
While trees, shrubs, herbs and creepers are all represented in the family, the common denominator is that they all have pods in which seeds are produced and they all have a symbiotic relationship with bacteria that form nodules on the roots, which are capable of fixing atmospheric nitrogen in return, for sugars obtained from the host plant.
These plants are important for maintaining and improving the nitrogen status of the soil and, in the case of rotational-field crops, are valuable in enhancing the fertility of the soil. By the same token, these plants are rich in protein and valuable as fodder crops. Under the ubiquitous thorn-tree Acacia karoo (sweet thorn or soetdoring), with its nutritious pods browsed by goats and sheep, the grass is always greener because of the nitrogen supplied to the soil.
An extensive family
According to Wild Flowers of KZN by Elsa Pooley there are about 642 genera with about 18 000 species within the Fabaceae family worldwide, of which about 144 genera are found in Africa.
Only the Asteraceae (daisy family, FW 22 February) and the Orchidaceae (orchid family) have more genera and species. The most prominent members of the family are the various acacias that grace our countryside from the dry watercourses of the western Karoo to the extensive savannas of the northern regions. Acacia karoo is the most well-known and widespread of all South African trees. It’s showy when in bloom in mid-summer and the bark, leaves and gum are used for medicinal purposes.
The karoo boerboon, Schotia affra, is one of a number of beautiful trees in this family. It’s brilliant-red flowers cover the hardy trees in the otherwise drab winter landscape of the southern and eastern Karoo. It’s highly palatable to stock and of great concern is that, in areas heavily grazed, no young trees are able to establish. We could lose a valuable treasure of the Karoo landscape.
The large beans of the boerboon have traditionally been used as counters (lotjies) by sheep shearers in the Karoo – a shearer takes one for each sheep shorn – thus keeping a tally according to which he receives payment. spectacular coral trees Erythrina, with their large orange and scarlet flowers that usually bloom in spring before the leaves appear, are also members of the Fabaceae family.
The bright red beans, often referred to as “lucky beans”, are produced in cylindrical pods that turn black when ripe. Most genera within the Fabaceae are smaller shrubs and shrublets, some are trees and many have a creeping habit. The genera include Lotononis (mostly blue flowers), Indigofera (mostly small shrubs with pink or red flowers) Psoralea, Crotalaria and Podalyria. These genera have numerous interesting species with attractive and colourful flowers and occur in a great variety of habitats all over South Africa.
An endemic genus, Aspalathus, with about 278 species, is the largest genus within Fabaceae. It’s a group of small shrubs mostly with yellow flowers sometimes spiny and with needle-like leaves. Rooibos tea made from the species Aspalathus linearis is a traditional beverage of the Khoi-descended people of the Cederberg. Not only is it a very pleasant drink, but it’s devoid of tannin and filled with other healthy elements.
Consequently it has become popular and an important commercial crop in the Clanwilliam, Citrusdal and Nieuwoudtville areas. Regrettably there is often a downside to a success story such as this.
The rapid expansion of Rooibos tea plantations threatens the existence of many rare, local fynbos plants in the region. Of particular concern is a small member of the Proteaceae, Serruria flava, endemic to the region which has now virtually been wiped out (see box: A damaging plantation of Rooibos tea).
Many members of the Fabaceae family are important medicinal plants. An example is Lessertia frutescens (cancer bush or kankerbos, formerly named Sutherlandia frutescens).
It’s an attractive, small, grey bush with brilliant red flowers that produce characteristic bladder-like papery pods. It has a wide distribution and is especially common in disturbed areas such as roadsides.
Decoctions of the plant are an old Cape remedy for stomach problems, internal cancer and a host of other ailments. Elephantorrhiza elephantina, with the common names elephant’s root and elandsboontjie, is another medicinal plant – fairly widespread in the summer rainfall grassland – which has several unbranched annual stems growing from an enormous underground rootstock. Clusters of small flowers are produced at the base of the stems and the plant has large pods. The underground rootstock is used for a wide variety of ailments including skin disease and acne.
Healthy honeybush
Honeybush tea produced from Cyclopia intermedia occurs in the Cape fynbos. It’s a multi-branched woody shrub growing up to 1m high. It has attractive yellow flowers and the seed pods are flat and brown. The tea is a uniquely South African herbal drink, originally used for medicinal purposes and it’s now harvested and commercially produced.
There is virtually no end to the number and variation of Fabaceae with each contributing positively to the functioning of the complex ecosystems in which they occur. It would be a worthwhile challenge for landowners to find, identify and record the species occurring on their land. – Cameron MacMaster ([email protected]) |fw
