Lithops - Au Cactus Francophone

colouration: (v) L. Fulleri also has dark coloured parts in the margin, which
are more pronounced than those of L. Aucampiae.
As a rule the margins show various degrees of indentation, although in
some species, as for example in L. olivacea, the inner margin is straight and
without markings. In many cases the margins develop laciniae and these are
sometimes fairly large and may approximate to teeth. These laciniae project
into the window and parts or the whole of the laciniae become separated from
the main body, thereby forming islands of various shapes and sizes in the
window.
In some species (L. Dinteri) there is a narrow band (1 2 mm. wide) of
a colour different from that of the rest of the top. In L. Dinteri this hand is
huff coloured and runs right round the window, whereas the rest of the top
surface is orange yellow.
GEOGRAPHICAL DISTRIBUTION
Lithops > Lithops
In examining the distribution of the genus Lithops in the southern
half of Africa, one is struck by the following interesting facts:—
(1) The genus reaches on the western side of South Africa its most
northern point at Franzfontein, near Outjo, S.W.A., latitude 20° S. (L.
gracilidelineata), whereas on the eastern side of this subcontinent it only
gets as far as Pretoria, latitude 25° 45´ S. (L. Lesliei).
45’ > 45´
L. terricolor is the only species which has migrated furthest south. It is
very interesting to note that this species has so far been recorded at various
places (Karroo Poort, Ceres, Laingsburg, Steytlerville, Springbok Flats, near
Port Elizabeth), all of which, although the two extreme points (Ceres and
Port Elizabeth) are hundreds of miles apart, yet lie approximately just a little
33 S > 33° S
south of latitude 33° S. Evidently there is some factor which has prevented
the species reaching the sea or getting nearer to the sea.
12’ > 12´ 16’ > 16´
Pretoria, longitude 28° 12´ E., and Bethlehem, 28° 16´ E., are the two
most easterly points the genus has reached in its march eastwards. Bethlehem
is so far the most easterly habitat so far recorded of the occurrence of this
genus. Here again one has the peculiar phenomenon that a single species (L.
Lesliei) has reached a certain longitude and evidently has not been able to
spread further eastwards than this line.
As regards its distribution towards the west of South Africa, the ge
nus has actually reached the seashore in some cases; for example, L. optica is
found in close proximity to the sea at Lüderitzbucht, L. Herrei near the sea
at Alexander Bay, L. Nelii not far from Cape Cross.
From the above it is apparent that this genus is confined to an area
bounded on the north by latitude 20 and in the south by latitude 33. On the
east its extreme boundary is longitude 28, whereas its western limit is the sea.
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