238 Wilson . — The Mucilage- and other 
that the enlarged cells secrete any of the calcium carbonate 
found resting on them. 
On the leaves of Statice articulata a somewhat similar 
condition obtains, the epidermal cells around the glands being 
often elevated into conical sculptured papillae (Fig. 7). Their 
arrangement is usually irregular, and they may occur singly 
or in groups without any connection with the glands. 
Statice cor data affords an example in which the glands on 
the upper side of the leaf are encircled by large cells, the lower 
of which project more prominently than the upper (Fig. 8). 
In the genus Limoniastrum , as represented by L. mono- 
petalum and L. Guyonianum , the Mettenian glands assume 
a very characteristic form, and function in a very marked 
manner as chalk-secreting organs. The glands lie sunk at 
the base of cup-shaped depressions. They have attracted 
much attention, and have been carefully investigated in 
L. monopetalum , chiefly and most recently by Woronin h 
The leaves of this species (Fig. 9), taken in arid regions, are 
thickly covered with calcium carbonate. Grown in this 
country, under glass, the secretion is not so great ; neverthe- 
less in summer the whole plant has a peculiar greyish aspect, 
due to the presence of innumerable dots of calcium carbonate 
on the stem and both sides of the leaves. When grown 
under a bell-glass in a high temperature and moist atmo- 
sphere the leaves are green and fleshy, the glands then 
appearing as minute translucent spots. Even under such 
circumstances, however, the cup-like cavities above the glands 
are filled with calcium carbonate. Much importance is to be 
attached to the fact, noted by previous observers, that after the 
mineral secretion is dissolved away a mucilaginous residuum 
is left. This indicates clearly enough the mucilage-secreting 
power of the leaf-glands in general. 
The condition of the leaf of Statice macrorrhabdos in respect 
to the quantity of calcium carbonate is striking (Fig. 10). 
Hairs, which may be regarded simply as pronounced forms 
1 Woronin, loc. cit. 
