Lithops - Au Cactus Francophone

figure 6 . lithops salicola l. bol.
In habitat. Lückhoff
Luckhoff > Lückhoff
MARGIN
One can consider the top surface of the two leaves as a circle, the fis
sure between the two leaves as the diameter. That part of the margin adjoin
ing the fissure is usually more or less straight and can be called the inner
margin. The semi circular part of the margin can be conveniently described
as the outer margin. In quite a number of species (L. Ruschiorum, L. gracili‑
delineata, L. turbiniformis) the whole top surface is undifferentiated, as it is
of a uniform colour and the texture is such that no distinct margin is vis
ible. In many other species, especially those with a large open window, there
is a distinct border to these windows. The margin is as a rule of no great
systematic value, although in certain cases the margin is a specific feature of
the plant and enables one to identify the species. The following species have
a distinct and characteristic margin; (i) L. optica, in this species the outer
and inner margins meet at the two extremities of the fissure and here a
charac teristic transparent triangle with the apex pointing downwards has been
developed: (ii) the margin of L. Otzeniana is laciniated, the outer consisting
of 10–12 laciniae, whereas that part of the inner margin along the fissure
is only 4–6 laciniated. The individual laciniae are either irregular, triangular,
somewhat oblong, obtuse or acute. They are 2–3 mm. in length and about as
broad as long. The margin of L. Otzeniana is typical of this species and the
reader is referred to the photographs. Some of the photographs were taken
of this plant in its natural habitat: (iii) the margin of L. Erniana has already
been noted and the reader is referred to the description of this species and
to the coloured drawing: (iv) that of L. Aucampiae shows a minute reddish
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