40 CHANDLER—UTRICULARIA PREHENSILIS. 
known under various synonyms—U. lingulata, U. hians, 
U. madagascariensis. : 
FLOWER STALK.—The origin of the flower stalk of U. pre- 
hensilis does not differ from that of U. vulgaris. It bears also 
at its base a mass of water shoots, leaves, and rhizoids. The 
flower shoot is twining, and the average length about 25 cm., 
sometimes longer. The flowering is more profuse than in U. 
vulgaris, and the flowers (see Fig. 1 and Stapf’s figures*) are yellow 
incolour. At the base of a flower stalk we find, as in other species 
of Utricularia, a number of rhizoids (Figs. 2 and 3). A limited 
number, usually three or four, are to be found also at some distance 
up the stalk. The rhizoids in U. prehensilis are not so rudi- 
mentary as in U. vulgaris, but are fairly well developed. The 
difference in habitat in the two species would account for the 
fact that in U. prehensilis the rhizoids are more developed, 
their use in the greater sub-stratum of mud being very much 
greater. As Gliick ~ has pointed out, the anchoring function of 
rhizoids is, to a large extent, lost in wholly submerged species, 
and the development of these organs is consequently not so great 
as in the sub-aquatic species. The rhizoids in appearance (Fig. 4) 
are very similar to those of U. neglecta figured by Gliick, ¢ but 
whereas in U. neglecta the leaves and rhizoids are alike, in U. pre- 
henstlis the appearance of the leaves, which are long and flat, in 
no way resembles that of the rhizoids. The rhizoids are divided 
into segments, the usual number being nine or ten on each side. 
The segments are simple, straight, and usually undivided, though 
occasionally at the base of an older rhizoid, division of the segment 
itself takes place (Fig. 4a) giving the rhizoid of this species thereaaiee 
general appearance of that of U. neglecta. The rhizoid segments 
are given off regularly and alternately at-right angles to the main 
axis. Unlike U. vulgaris the tips of these segments do not 
possess circinate ptyxis, but are straight like the growing points 
of the water shoots. The segments are covered entirely with 
glands, except at the very tip and base (Fig. 4). Glands also 
are present at intervals on the main portion of the rhizoids. These 
thizoids measure some two to three times the length of the rudi- 
mentary rhizoids of U. vulgayis. Whereas, too, in this latter 
species, metamorphosis of the rhizoids into ordinary water shoots 
is common, in U. prehensilis the rhizoids are organs apart from 
the water shoots, and in no case was metamorphosis observed. 
MorPHoLocy.—In diameter the flower stalk is about 1=1.5 mm., 
and is characterised by a reduction of aerenchyma compared to 
the water shoot. The amount of aerenchyma is naturally 
greatest at the base of the flower stalk which is under water. 
* Stapf in Hooker's Icones Plantarum, t. 2768. 
¢ Glick, loc. cit. + Glick, tot. oft, «Tata, 
