CHANDLER—UTRICULARIA PREHENSILIS 4t 
A section across the middle of an aerial flower stalk shows 
(Fig. 5) a distinct epidermis, composed of large cells somewhat 
thickened on their outer walls, bounding the section. A small 
amount of aerenchyma and large round cells, loosely arranged, 
form the cortex. The endodermis is composed of large clear 
cells thickened on their radial walls. A ring of xylem surrounds 
the pith with small scattered patches of phloem. There are also 
one or two irregularly distributed patches of vascular tissue in 
the ground tissue, as in U. emarginata * and U. brachiata.t The 
pith cells are small in the vicinity of the xylem ring, but very 
large towards the centre of the section. 
As well as rhizoids, a great number of ordinary water shoots, 
bearing leaves and bladders, are to be found at the base of an 
aerial flower stalk, and the leaves are often found springing 
immediately from the base. In structure the water shoots are 
simple, having a central vascular strand, surrounded by air 
tissue and epidermis (Fig. 7a). As in all other parts of the plant, 
the water shoots are covered at intervals with small projecting: 
glands. 
The leaves are given off as branches of the water shoots. At 
their base they do not differ in any respect from the shoots them- 
selves, but when the flattening of the leaf begins, the main nerve 
divides into three, so that a section of a leaf shows three vascular 
strands surrounded by air tissue, and an epidermis composed of 
slightly thicker and polygonal rather than brick-shaped cells, as at_ 
the base, or in a section of the water shoot (Figs. 6and 7). Stomata’ 
with two guard cells are found at intervals on the leaves with the 
glands. | 
The bladders differ in shape from those of U. vulgaris (Fig. 8). 
Their origin and development are as in other species of Utricularia, 
each one arising as a roundish knob on a stalk, which is compara-. 
tively long when fully developed. The bladders of U. prehensilis do 
not possess hairs at the mouth, but two horn-like elongations of the 
bladder itself (Fig. 8a). The interior of the bladder is characterised 
by the absence of quadrifid processes, and is covered only with 
bifid processes (Fig. 9). The collar is densely covered with 
stalked glands all of the same shape, while other glands, bicellular 
in construction, form a transition near the exterior to the pro- 
jecting glands without stalks, with which the whole exterior of 
the bladder and the stalk is covered, as are all other submerged 
parts of the plant. Inside the bladder, decayed brown matter is 
found, but no distinct entire micro-crustacea. The fact that the 
bladders of this species are sunk in mud, and therefore more liable 
to decay, would explain this. 
* Chandler, in Ann. Bot., xxiv (1910). 
+ Compton, in New Phytologist, April 1909. 
