Lithops - Au Cactus Francophone

which he named Mesembryanthemum turbiniforme, as follows; Planta acaulis,
obconica, superne truncate obscuro punctata. The plant was subsequently re
named Lithops turbiniformis by N. E. Brown. This discovery was made by
Burchell on September 14th, 1811, at Zand Vlei, in the Prieska district (Fig.
1). More than a hundred years elapsed before this plant was rediscovered by
Pole Evans in more or less the same locality as that in which it was found
by Burchell. The next species to be described was named Mesembryanthemum
pseudotruncatellum by Berger in 1908. This plant was found in Damaraland,
Great Namaqualand, and as we now know, in the vicinity of Windhoek. In
1912 Mr. Leslie discovered near Vereeniging a plant, named by N. E. Brown
Mesembryanthemum Lesliei after its discoverer. These early discoveries show
that the genus has a very wide distribution, as Windhoek and Vereeniging lie
far apart and they are both about 500 miles from Prieska.
During the period 1920–1933, large numbers of species were discovered
both in the Union of South Africa and in South West Africa.
Kurt Dinter, the indefatigable collector, deserves to be mentioned, for
it is largely due to his enterprise that our knowledge of this genus has been
so appreciably increased. It must be borne in mind that he undertook his
collecting tours by oxcart and under very arduous conditions, as the majority
of the South West species occur in the most arid and uninhabited parts of
that dry country. One requires a knowledge of the country to know where to
look for species of Lithops, as these plants are perhaps the most difficult of
all to find in the field and a fairly sharp eye and one might almost say intuition
are needed to find them. In the dry condition one walks on these plants without
seeing them.
Each individual plant consists of more or less contiguous leaves on a
short stem. The whole diameter of the plant varies from about 0.5 to 5 cm.,
the latter being an extreme case, as these plants are usually about 1–2 cm.
in diameter. In some plants, the two leaves are separated by a very narrow
fissure and in others the lobes, at least in the old stage, stand firmly apart
from one another (L. divergens, L. Comptonii, L. Helmuti).
4
STEM
As mentioned above, each individual plant consists of two more or
less contiguous leaves on a short stem, the cross section of which is circular.
The length of the internode is about the same as the thickness of the leaf,
and is named the insertion zone. The stem is therefore not free, but only
becomes so after the succulent leaves have shrunk and perished. The remains
of the old leaves are dry and papery, and they protect the young leaves in
their early, stages of development.
In the young stage the plant does not branch at the growing point of
the stem, i.e. at the base of the fissure, but a new pair of leaves is formed