Cuar, XV} PINGUICULA VULGARIS. ' 297 
CHAPTER XVI. 
PINGUICULA. 
Pinguicula vulgaris—Structure of leaves—Number of insects and other objects 
caught—Movement of the margins of the leaves—Uses of this movement 
—Secretion, digestion, and absorption—Action of the secretion on various 
animal and vegetable substances—The effects of substances not containing 
soluble nitrogenous matter on the glands—Pinguicula grandiflora—Pin- 
guicula lusitanica, catches insects—Movement of the leaves, secretion and 
digestion, 
PixevicuLa vuLearis.—This plant grows in moist places, 
generally on mountains. It bears on an average eight, 
rather thick, oblong, light green * leaves, having scarcely 
any footstalk. A full-sized leaf is about 1} inch in length 
and 2 inch in breadth. The young central leaves are deeply 
concave, and project upwards; the older ones towards the 
outside are flat or convex, and lie close to the ground, form- 
ing a rosette from 3 to 4 inches in diameter. The margins 
of the leaves are incurved. Their upper surfaces are thickly 
covered with two sets of glandular hairs, differing in the 
size of the glands and in the length of their pedicels. The 
larger glands have a circular outline as seen from above, and 
are of moderate thickness; they are divided by radiating 
partitions into sixteen cells, containing light-green, homo- 
geneous fluid. They are supported on elongated, unicellular 
pedicels (containing a nucleus with a nucleolus) which rest 
on slight prominences. The small glands differ only in being 
‘formed of about half the number of cells, containing much 
paler fluid, and supported on much shorter pedicels. Near 
the midrib, towards the base of the leaf, the pedicels are 
multicellular, are longer than elsewhere, and bear smaller 
glands. All the glands secrete a colourless fluid, which is 
so viscid that I have seen a fine thread drawn out toa length 
* [According to Batalin (‘Flora,’? green in plants grown in shady places. 
1877) the yellowish-green colour is It is due to a yellow homogeneous 
peculiar to plants grown in strong substance found in the epidermal 
light, being replaced by.a more lively cells andin the glands.—F. D.] 
