THE FLORA OF THE COUNTRY
“South-West Africa,” a writer on the flora of the country has recently
stated, “is distinguished neither by a great variety of its flora nor
by the presence of plants or trees of any singular kind.” How far this
is from the truth will be made clear in this chapter.
For a dry country South-West Africa is fairly rich in vegetation, and
it may be useful to give some slight impression of the part which the
vegetation plays in the landscape and in the economic conditions of the
country, cursory though our examination must be.
THE COAST REGIONS
To begin with the Namib. The general aspect of the vegetation here is
monotonous, since there are but few plants that rise to any appreciable
height from the sandy surface to break the dull level. No tree grows
within a dozen miles of the coast, except in an occasional watercourse
where there is underground moisture.
The Kokerboom, _Aloe dichotoma_, however, often occurs as a solitary
tree, and occasionally forms little groves on the limestone hills of
the eastern portion of the Namib. In the winter, when they bear large
clusters of bright yellow flowers, they give quite a touch of colour to
the drab landscape.
The northern Namib has two plants of singular interest in the
Welwitschia and the Naras. The Welwitschia, _Welwitschia Bainesii_, is
in reality a tree with a fairly thick trunk that terminates abruptly
just above the ground. Two thick, leathery leaves are permanent and
grow continuously at their base until they sometimes reach a length of
10 feet, by which time they are frayed into numerous snake-like thongs.
The plant flowers in January and the cones ripen in May. The roots of
the largest plants may be traced to a very great depth in the sand.
“This plant,” says Dr. Marloth,[5] “is of great scientific interest,
being the most highly developed gymnospermous plant known to us either
in the living or the fossil state. It is not a connecting link between
the gymnosperms and the angiosperms, but the final stage of a separate
line of development of the vegetable kingdom, that, as far as is known
to us, led no further.” The Welwitschia was first discovered by Dr.
Welwitsch in Southern Angola in 1865. It has not been found south of
the Kuisip district.
The curious Naras, _Acanthosicyos horrida_, has been well termed
the “Wonder of the Waste,” for this shrubby, leafless member of the
order _Cucurbitacea_ spreads over the sand dunes in dense straggling
masses, defying all the sandstorms that threaten to bury it. Instead
of tendrils it bears sharp thorns, while the main root may be as thick
as a man’s arm, with a length of 20 to 40 feet. The fruit is about the
size of a very big orange, and the skin encloses a yellow pulp of a
rich flavour and a number of seeds similar in taste to almonds. The
fruit is greatly relished by the natives, and, as it has extraordinary
nutritive value, they almost live on it. The seeds are stored for the
dry season, when no fruit can be obtained. The existence of this plant
always indicates underground moisture. Both the Welwitschia and the
Naras flourish in the vicinity of Walvis Bay, but the Naras has been
found in recent years in several places in the southern Namib. It is
believed that the species does not occur naturally so far south, but
has been introduced by natives. Its true southern limit is not far from
the southern extremity of Walvis Bay.[6]
In the region described as the Upper Kuisip Zone, which embraces the
valley of the Kuisip, among the fairly abundant vegetation, with
camelthorns, ebony trees, and wild figs, the handsome Ana tree,
_Acacia albida_, is found. The fruit of this remarkable tree is a
legume. The beans, when ripe and dry, are used for fodder for cattle,
and they have extraordinary fattening properties. Cattle also relish
the leaves of the tree.
The flora of the desert south of Luderitzbucht is much poorer than that
of the northern portion, and, as Schinz points out, the difference is
probably accounted for by the presence of a more copious supply of
underground water in the northern area. But the Namib has a richer
vegetation than is generally supposed.
“As an illustration,” writes Dr. Marloth, who made a careful
examination of the Lower Namib in 1909, “it may be mentioned that I
have observed over twenty species of _Mesembrianthemum_, five species
of _Pelargonium_ (mostly shrubby), two of _Sarcocaulon_, three of
_Lycium_, two of _Zygophyllum_, two of _Salsola_, three of _Othonna_,
five shrubby Leguminosæ (_Lebeckia_ and _Crotalaria_), five species
of _Euphorbia_, and many other genera represented by one or two
species.”[7]
He distinguishes four formations according to the nature of the ground:
the seashore, the sandy plains, the rocky hills, and the gravel-covered
flats of the rising plains beyond the coast-belt; and we cannot do
better than adopt his convenient division.
_The seashore._--The sand dunes are devoid of vegetation on account of
the ever-shifting nature of the sand, and they present an unforgettable
scene of sterility and dreariness. A few plants specially adapted to
salt water, such as _Salicornia natalensis_ and _Bassia diffusa_, are
found in the shallows or around the lagoons.
_The sandy plains and dunes._--Further inland _Salsola Zeyheri_ is
common. This low, tight-looking shrub, grey in colour, about 2 to 3
feet in height, has considerable value, since it forms good food for
the camels used for transport purposes. Coarse dune-grasses are found
in sheltered patches. The _Mesembrianthemum_ is a characteristic Namib
plant; it grows on rocks as well as sand.
_The rocky hills._--Here we find a more varied vegetation. The
well-known Kokerboom (_Aloe dichotoma_) is a conspicuous feature. It
is interesting to notice that the name Koker or Quiver (D. _koker_, a
case sheath; G. _Kocher_, a quiver) was given to this tree because the
Bushmen and Hottentots used the pithy branches to make quivers for
their poisoned arrows.
Even more numerous than the _Aloe dichotoma_ are several species
of _Euphorbia_. Schinz, it may be noted, has described the eastern
edge of the desert as a Euphorbia-steppe.[8] The _E. gummifera_ is,
perhaps, the most noticeable plant, and in the Garub region this
species abounds. It forms compact bushes, 3 to 6 feet in height, and
its grey twigs have rather an unpleasant scent, while they contain
an unusually rich supply of milk juice. The _E. cervicornis_, the
olifant melkbosch of Little Namaqualand, is found occasionally. A
little plant that crouches behind rocks or isolated stones is the dwarf
shrublet _Pteronia succulenta_, whose main stem is often bent over at
a right angle by the fierce winds as soon as it pushes its head above
the shelter. Other plants, usually forming upright bushes, are here
compelled to bend before the strong winds; notable among these is the
_Pituranthus aphyllus_, a leafless umbellifer.
A plant of peculiar interest found among the many species of
_Mesembrianthemum_ is the _M. rhopalophyllum_, which is remarkable for
its highly-specialised window-leaves. “The plant grows embedded in the
sand, nothing but the flat, slightly convex apex of each leaf being
visible, and even that is covered with more or less sand according to
locality. While the leaf itself is fresh green with a rather delicate
skin, the exposed part is protected by a thick epidermis and cuticula,
and possesses comparatively few stomata. It is through this portion,
which has the functions of a window, the leaf receives its light, being
thus illuminated from within. There are five to ten, or even more,
leaves to each plant, but nothing appears at the surface except these
windows; they peep out of the sand like the eyes of the sand-lizard or
sand-vipers, which often hide themselves in a similar way.”[9]
It is very curious to see the short flowers of these plants in the
spring, for they grow, apparently, straight out of the sand. Only
on investigation are the leaves and stem discovered. The leaves are
club-shaped. Nature has evidently chosen this underground mode of
existence for the plant in order to protect it against the herbivorous
animals. These interesting plants are found only in Africa.
The leaves of the _Augea capensis_ are very strong in sap, but the
plant is so salty that even the camels will turn away from it. This
plant is found in many parts of the Karroo.
An untidy-looking shrublet, the _Sarcocaulon rigidum_, is fairly
abundant. A peculiarity of its structure is the sharp-pointed spines,
which are specially modified stalks of former leaves. Leaves of vivid
green cover these plants in the spring, and at times they are numerous
enough to influence the colour of the landscape. Pink flowers appear on
them in October.
_The gravel plains._--The rising plains of the inner Namib, which have
an altitude of 1,800 feet, some fifty miles from the coast, are swept
by furious sand-laden winds for the greater part of the year. The
sea-fogs rarely reach these areas, and, as the rainfall is a negligible
quantity, no sign of life may be encountered for many miles, only a
vast, monotonous waste of gravel and sand meets the eye. Occasionally
one lights upon the typical _Sarcocaulon rigidum_, the Candle-bush or
Bushman’s candle. This plant has been specially adapted to meet the
conditions of the desert, and it is able to defy the hottest sun and
the fiercest sandstorms. Layers of corky tissue, impregnated with a
mixture of fat, wax, and resin, form the bark. This horny casing is the
plant’s armour against the attacks of its enemies. It burns steadily
like a wax candle with a yellow, smoky flame, even when cut fresh from
the ground.
THE CENTRAL PLATEAU
Beginning with Ovamboland, we find considerable forest tracts of
acacia, with giant baobabs, and palms and fig-trees in the more
open park-like spaces. The palm zone is found some distance south of
the Kunene. Grasses cover the extensive plains after rains. On the
uplands of Damaraland the genus Acacia plays an important part in the
composition of the flora; in many places it predominates among the
bushes and also among the trees.[10] With the acacias are found other
notable species, including _Combretum primigenium_, and the large
_Ficus dammarensis_.
The handsome Ana tree, _Acacia albida_, is frequently met with. The
mountain valleys have a much more luxurious vegetation than the hills,
since they are watered by the many rivulets that abound after rain.
On the eastern steppes where the country is sandy and poor in
vegetation, that typical product of the Kalahari desert, the tsama
melon, _Citrullus vulgaris_, is found. Both man and beast rejoice in
this juicy melon. In its raw state it has remarkable thirst-quenching
properties, and when cooked it is a satisfying food. The seeds are
oily and very fattening. This fruit often affords the only supply of
water for travellers in this dry and dreary region. That queer little
plant, known as Uyntjes, a kind of sedge, is also found in this region,
and the bulbous roots, not unlike the chestnut in flavour, are used
as food by the natives. In the springtime a species of Brunsvigia, or
Candelabra flower, sometimes covers large areas of the open country.
Great Namaqualand is not so well wooded or so well watered as
Damaraland. The kokerboom is a conspicuous feature on the hills.
North of Warmbad a bush formation is encountered in the vicinity of
the dry river beds, with _Acacia detinens_, _Cadaba juncea_, shrubby
Zygophyllaceæ, _Parkinsonia Africana_, and trees of _Acacia horrida_.
Camelthorns (_Acacia Giraffæ_) are numerous on the higher levels. The
Twagras, or Bushman grass of the Karroo, _Aristida brevifolia_, is a
characteristic feature of the vast plains. Even when dry this grass
retains its nourishing properties, and a period of two years may pass
before it dies. The grey hills that border the Orange River have only a
few kokerboom and chips of the _Euphorbia virosa_, and some straggling
sickly shrubs of _Bauhinia garipensis_.
FOOTNOTES:
[5] “The Flora of South Africa,” Vol. I., by Rudolf Marloth.
[6] Pearson, “The Travels of a Botanist in South-West Africa”--_The
Geographical Journal_, May, 1910.
[7] “The Vegetation of the Southern Namib”--_The South African Journal
of Science_, January, 1910.
[8] Schinz, “South-West Africa,” Leipzig, 1894.
[9] “The Flora of South Africa,” Vol. I. Rudolf Marloth.
[10] Pearson, “The Travels of a Botanist in South-West Africa”--_The
Geographical Journal_, May, 1910.