Lithops - Au Cactus Francophone

which enclose between them the new growing point. These leaves are pro
tected by the original cotelydonary leaves. The leaves are opposite and they
alternate with the old leaves which, after the new leaves are developed, die
and disappear. In this manner the growing point produces annually a pair of
leaves, which are decussate to the previous ones and to those that follow.
The plant flowers at a later stage and the flower is formed terminally.
On both sides of the terminal flower a new leaf pair is formed.
LEAF
The two leaves together form an inverted cone, the base of which is
exposed to the atmosphere and the apex is embedded in the soil. The base
of this conical structure we can call the top, and the sides the mantle. For
purposes of classification it is the base which is of paramount importance.
The mantle, which is almost impervious to water, is in immediate contact
with the soil and thus very little light reaches it. Immediately within the
mantle is a thin layer of green tissue—chlorenchyma or food making tissue
of the plant. The central tissue of the inverted cone is transparent and serves
for water storage, and the shape of the cone varies within certain limits ac
cording to the degree of turgidity of the plant. Fig. 2 gives an idea of the
general structure of the plant as a whole. The sinking of the plants in the
soil is a protection against desiccation.
The top of each of the two leaves, which together form the conical
figure 2 . lithops weberi nel.
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