CHAP. II. 
STOMATES. 
53 
species. That is to say they are composed of a pair of cells 
placed side by side, communicating freely with a hollow 
chamber in the parenchyma of the leaf built up of cells, 
arranged in various ways. {Fig, 14. c represents the appear- 
ance of the stomate in Acrostichum alcicorne when cut through 
perpendicularly ; Jigs, d and g show it in the seed-coat of 
Cannas, and jig. f is the appearance of the same stomate 
seen from above ; all these are copied from Dr. Schleiden’s 
figures.) It is not, however, always two cells which by lying 
side by side form the stomate ; occasionally a greater number 
is present ; as in Marchantia, where, according to Mirbel, they 
are minute funnels in the epidermis, composed of four or five 
vesicles arranged circularly in several tiers ; at the bottom of 
this funnel is a large square aperture, communicating with a 
subjacent chamber, and caused either by the destruction of a 
central vesicle, or by the separation of the sides of four or 
five vesicles at the angles next the centre of the funnel. 
Several varieties are represented at Plate III.; besides 
which, stomates have been noticed by Link to be occasionally 
quadrangular, as in Yucca gloriosa (Plate III. fig. 10.), and 
Agave americana, and by Brown to be very rarely angular, 
of which, however, no instance is cited by that botanist. The 
former case is one in which the quadrangular figure is caused 
by the cellules of the opening being straight, and bounded by 
four other cells which appear to be inside the areolations of 
the cuticle. I have never been so fortunate as to discover the 
membrane which this great observer describes as generally 
overlying the apertures ; nor do I know of any other botanist 
having confirmed that observation. It cannot be the cuticle 
already described, because it has been found that that part 
never overlies the stomates (see page 50.). 
Nerium oleander, and some other plants have, in lieu of 
stomates, cavities in the cuticle, curiously filled up or pro- 
tected by hairs. (See Annates des Sciences^ xxi. 438.) 
In Nepenthes there are stomates of two kinds, the one 
oblong, semi-transparent, and almost colourless, with numerous 
pellucid globules in the cavity of the cells ; the other roundish, 
much more opaque, and coloured red. The latter do not 
communicate immediately with internal cavities in the paren- 
E 3 
