The grass family contains more species than any other family of flowering plants, and grasses directly or indirectly, provide the bulk of the world’s food. The cultivated domestic grasses, barley, maize, millet, oats, rice, sorghum and wheat provide food directly through the harvesting of their seeds other grasses provide food indirectly through grazing animals. Cattle, sheep and goats convert grass, which is unsuitable for human food into meat which is a high protein human food.
“Veld” is an Afrikaans word which has been adopted in Africa to refer to the natural grazing, and is made up mainly of grasses, but also shrubs and trees.
In Africa more than 90% of the land is covered in veld which is natural vegetation, and the livestock industry is based on converting the grasses of the veld into meat. There are thousands of grass species found in Africa. This lecture lists the names of about 50 of the common species and illustrates a few examples.
The Ecology of grasses is the study of where certain grasses will grow i.e. their habitat, and why they grow in that particular area. Each grass prefers certain conditions of soil, moisture rain or ground water, temperature, shade etc. Some grasses will disappear from the veld under adverse conditions such as heavy grazing or disturbance of the soil, and those grasses together with the grasses that replace them can be used as indicators of whether the veld is stable or disturbed. When the veld is stable, it contains the grasses which can make the best possible use of the climatic and soil conditions. These grasses are called the climax species: When the veld is disturbed or over-grazed, rainwater does not penetrate the soil to the same extent because it runs off the bare soil. This results in the climax species being replaced by grasses which are lower down the scale of succession because these grasses need less moisture, can withstand heavy grazing and can start to grow in bare soil. An example of this is Hyparrhenia, a climax grass, being replaced in the veld by Sporobolus which is a poorer grass.
Grasses can become sick and die out like any other plant or animal. Veld management aims to keep the most desirable grasses on the veld, and in a healthy state. Keeping the climax grasses on the veld performs the following functions
- The maximum amount of forage is available for the grazing animal.
- The soil of the veld is covered by herbage and this helps rain water to penetrate the soil and prevents run-off from the soil surface.
2. THE GRASS PLANT
In order to identify the different grasses it is necessary to know their characteristics and the botanical terms used to describe them. The diagram on the following page shows the main Stem of the grass plant and the three types of flowering heads that appear on different grasses.
Figure 1: Stem of the grass plant and flowering heads of the grass plant
Grasses are either annual, completing their life cycle in one year, or they are perennial and live for two or more years.
These are fibrous and occur at the base of the plant, and sometimes at the joints of the stems.
Grasses that are tufted have upright stems and form thick tufts of leaves, stems and roots. Runner grasses send out horizontal stems which root at the joints and form new plants; these grasses spread very quickly, an example being couch grass or star grass. The horizontal stems can be stolons, which run along the ground, or rhizomes which run under the ground.
The main upright stem is called the culm and the joints in the stem are called nodes. The culm bears leaves from most of the nodes and ends in the flower head or inflorescence. The culm can be simple or it can be branched.
These consist of the lower part known as the leaf-sheath and the upper part known as the blade which hangs away from the culm. Where the leaf-sheath and the blade join, there is usually the ligule on the upper surface and the collar on the lower surface. The ligule can be a membrane or a ring of hairs and can be useful for identifying a grass. Leaf-sheaths and blades vary in shape, size, colour, margins,(smooth or.serrated) and whether they are rolled, folded or expanded.
This bears the flowers and later the seeds of the grass plant. Flowers are borne between two small modified leaves called bracts and the flower and the bracts form a floret. Florets either single or in groups, have two more bracts called glumes at their base, and the whole group is called a spikelet. In many grasses, for example Hyparrhenia, one of the bracts extends to a bristle called an awn.
When the spikelets are carried on the sub-division of a branch, the flower head is called a panicle as in Panicum grasses. Where the primary branches of the flower-head have no sub-divisions, the head is called a raceme or a spike.
SOME COMMON GRASSES OF AFRICA
The following list gives the common names and the botanical names of a few of the common veld grasses of Southern Africa (South of the Zambezi). Most of them are also found in East Africa.
|Botanical Name||Common Name|
|Alloteropsis semialata||Black seed grass|
|Andropogon gayanums||Blue grass|
|Andopogon eucomis||Snowflake grass|
|Aristida congesta||Bristle grass|
|Aristida junciformis||Steekgras. Ngongoni|
|Bothriochloa insculpta||Pinhole grass|
|Bothriochloa glabra||Purple Tassle|
|Brachiaria nigropedata||Black Footed Brachiaria|
|Brachiaria serrata||Velvet Signalgrass|
|Cenchrus ciliaris||Blue Buffalo Grass. Foxtail|
|Botanical Name||Common Name|
|Chloris gayana||Rhoes grass|
|Chloris virgata||Old Land grass|
|Cymbopogon excavates||Turpentine grass|
|Cymbopogon plurinodis||Bushveld Turpentine|
|Cynodon dactylon||Couch grass, Kweekgras|
|Dactyloctenium giganteum||Giant Crows Foot|
|Digitaria diagonalis||Finger grass|
|Digitaria eriantha||Smuts Finger grass|
|Digitaria sanguinalis||Crab Finger grass|
|Diheteropogon filifolius||Wire Bluestem|
|Eleusine indica||Goosegrass, Osgras|
|Elonurus argenteus||Wire Lemongrass|
|Eragrostis capensis||Heartseed Love grass|
|Eragrostis curvula||Weepeing Love grass|
|Eragrostis plana||Mchigi. Fan Love grass|
|Eragrostis rigidior||Curly Leaf Love grass|
|Eragrostis superb||Heart Love grass|
|Hemarthria altissima||Swamp grass|
|Heteropogon contortus||Spear grass|
|Hyparrhenia filipendula||Thatching grass|
|Hyparrhenia hirta||Short Thatch grass|
|Hyparrhenia rufa||Tall Thatch grass|
|Botanical Name||Common Name|
|Hyperthelia dissoluta||Yellow Thatch grass|
|Loudetin simplex||Russet grass|
|Monocymbium ceresiiforme||Oat grass|
|Panicum coloratum||Buffalo grass. Bambatsi grass|
|Panicum maximum||Guinea grass|
|Paspalum dilatatum||Dallis grass|
|Paspalum notatum||Bahia grass|
|Pennisetum purpureum||Elephant grass. Napie Fodder|
|Pogonarthria squarrosa||Cross grass|
|Rhynchelytrum repens||Natal Red Top|
|Setaria sphacelata||Golden Millet|
|Sporobolus africanus||Rats Tail Drop seed|
|Sporobulus pyramidalis||Cats Tail|
|Themeda triandra||Red Grass|
|Trachypogon spicatus||Giant Spear grass|
|Tragus racemosis||Carrot Seed|
|Tristachya hispida||Red Seed Grass|
|Unochloa mosambicensis||False Paspalum|
A few of these common grasses are illustrated on the following pages so that you can get an idea of their appearance. The illustrations are taken from the book Common Veld Grasses of Zimbabwe by Mr. C. Lightfoot and published by the Natural Resources Board.
There are 16 species of this grass of which 8 are annuals. The flowers do not have awns, and the grass is a climax, good grazing grass.
- Chloris gayana
Rhodes Grass. A perennial grass propagated by seeds. The Katambora strain is used in crop rotations because it is resistant to nematodes (eelworms). The grass is used for grazing and for making hay.
- Cynodon Dactlyton
Couch Grass. A perennial grass which spreads by means of underground rhizomes. Star Grass is an improved variety which is used as a pasture grass and gives good grazing for both sheep and cattle.
- Eleusine indica
Goose Grass. This can be either an annual or a perennial and is a troublesome weed in cultivated lands.
- Hyparrhenia Filipendula
Thatching Grass. There are a number of species of Hyparrhenia in Southern Africa, all of them being perennial and tufted. This grass is dominant in high rainfall areas, and grows on both clay soils and sandy soils. Where land is left to revert from arable to veld, this grass will eventually take over.
- Hyperthelia Dissoluta
Yellow Thatching Grass. Perennial and tufted, this grass grows on both moist and dryland in the highveld. Like all the thatching grasses it is palatable when young but becomes unpalatable as it grows older.
- Heteropogon Contortus
Spear grass. A tufted, perennial grass common in areas of medium rainfall. The sharp seeds can cause irritation and infection to animals and they can damage hides and meat. When the awn is wetted, it twists to drive the seeds into the ground. Average fodder value.
- Pennissetum purpureum
Napier Fodder or Elephant Grass. Tufted, perennial and very tall, normally growing up to 2 – 3 m high. Commonly cultivated, and can be grazed intensively in spring and cut for silage in summer.
Two other species of this grass are Kikuyu grass which is a good pasture grass and which is Bulrush or Pearl Millet grown in dry areas for the seeds.
- Digitaria Diagonalis
Finger Grass. Tufted, perennial which grows on sand veld with moderate or good rainfall. A climax grass which gives good grazing. There, are 30 species of finger grasses.
- Loudetia Simplex
Russet Grass. A short, densely tufted perennial. A common semi-vlei species often found on poor, leached areas of veld in the cool moist areas. A poor sour unpalatable grass.
- Panicum Maximum
Guinea Grass. Tufted perennial propagated by seeds. Grows best on fertile soils, and makes good hay and winter grazing. Loses vigor if it is heavily grazed in summer.
- Paspalum Orbiculare
Common Native Paspalum. A short, perennial grass. Common on wet sand- veld vleis in the middle and sourveld. Average fodder.
Lovegrasses. There are 62 species of this grass in Southern Africa, some annual and others perennial. Most of them are weed grasses of poor grazing value.
- Rottboelia Exaltata
Guinea Fowl Grass. Annual grass which gives good grazing but is unpleasant to handle because of the stinging hairs on the leaf-sheaths.
- Setaria Pallidifusca
Timothy. Short, annual grass which is a common dry land veld weed in disturbed areas of poor fertility. Average fodder but very little bulk.
- Sporobolus Pyramidalis
Cats Tail Grass. Perennial, densely tufted and very difficult to pull up. A very common weed in moderate rainfall areas, and troublesome in pastures. Poor forage and very unpalatable. There are 25 species common in the country.