241 
Glands of the P lumbagineae. 
removing a portion of the epidermis from the base of the 
petiole. Their outline is in general oval. They are most 
numerous close to the junction of the stem and leaf, and are 
confined to the latter. In large leaves they may be distributed 
half an inch above the axil. Sometimes they are restricted 
to a relatively narrow space. Seldom are they so numerous 
as to overlap one another as in Staiice macrorrhahdos 
(Fig. 20, o). 
The upper surface displays the appearance of being formed 
of very numerous extremely thin- walled cells; the base is 
composed of relatively few stout-walled ones (Fig. 20, c, b). 
A vertical section of a fully developed gland (Fig. 21) shows 
that the secreting cells are prismatic, columnar or conical. 
They radiate from the basal cells, and may or may not be 
divided by a few transverse septa. The contents are finely 
granular. Now and again, more especially in young glands, 
nuclei may be seen. After staining, a vacuolated appearance, 
due probably to the accumulation of mucilage, particularly 
towards the periphery of the gland, can be detected. As to 
the method of discharge, it seems to be accomplished by 
simple exudation, not by gradual accumulation of mucilage 
under, and subsequent rupture of, the cell-membrane. The 
mucilage is evidently highly hygroscopic, and is thus often 
so fluid as to be easily mistaken for water. On the other 
hand, it can be dried to form brittle, delicate sheets and 
shreds. In alcohol it hardens as an opaque white substance 
of considerable toughness. It is innocuous ; and Cocci are 
attracted to it, as they are to the secretion in the axils of the 
stipules of Cinchona 1 . 
In three cases, viz., in adult Statice sareptana and 5 . Caspia , 
and a rather young .S. Thouini , a few mucilage-glands have 
been found elevated on conical epidermal projections (Fig. 
22), recalling, in some measure, the calycine glands of 
Plumbago. 
1 See Lawson, ' Cinchonaceous Glands/ Trans. Bot. Soc., vol. v. Part T, 
1856, p. 3. 
R 
