PLANTS WITH TRAPS AND PITFALLS TO ENSNARE ANIMALS. 123 
is the sphere of activity of an individual Utricularia nelumbifolia. This plant 
is remarkable also from the fact that long runners are thrown out from its stems, 
which grow across, in wide arches, from its cistern to a neighbouring Tillandsia, 
where it selects one of the reservoirs in the rosettes as a new site and dips down 
into the water—a fantastic method of propagation of which we shall speak again 
on another occasion. 
A few Utriculariz do not live in water at all, but grow amongst mosses, liver- 
worts, and lycopods, in the vegetable mould filling the clefts and crevices of rocks, 
and the bark-fissures of old trees. Of this habit, for example, is the pretty 
Brazilian Utricularia montana, which, in spite of the difference of its habitat, is 
provided with an apparatus for capturing animals agreeing in all essential respects 
with the description already given. The bladders used by these plants for pur- 
poses of prey are produced on subterranean filiform stems which thread their way 
in the vegetable mould and wefts of decaying moss-stems, and here and there swell 
into tubers. The bladders are hyaline and transparent, and are filled with watery 
liquid, sometimes also with air. They are only 1 millimeter in diameter, but are 
present in large numbers. The entrance into these bladders is much more con- 
cealed than in the species that live in water. The dorsal surface of the bladder 
being still more strongly curved, the position of the orifice is altered so as to be 
quite close to the little stall of the bladder. In addition, the orifice is, as it were, 
roofed over, and thereby protected against the possibility of being stopped up by 
particles of earth, and the passage leading to it is very narrow. That, in spite of 
the difficulty of entrance, a number of minute animals do seek a hiding-place here 
is proved by the circumstance that, besides various infusoria, rhizopoda, and 
creatures of that kind inhabiting damp earth, species of Acarus and larve of 
other animals have been found, both dead and alive, in the bladders. 
With this first group of insectivorous plants, wherein the capturing apparatus 
includes a valve to prevent the egress of such animals as fall into the trap, is 
associated in the first section a second group, viz. that of the ascidia-bearing or 
pitcher-plants, in which the foliage-leaves are converted into pitfalls, and the 
escape of the captured prey prevented by a number of points lining the inner 
wall of the cavity, and directed from the aperture towards the closed bottom. 
There is an extraordinary variety in the form of the pitfalls. Sometimes they 
are tubular, utricular, or funnel-shaped cavities, sometimes mug or pitcher-shaped, 
or urceolate; in some cases these are straight, in others bowed like sickles, or 
spirally twisted. They always arise from the part of the petiole upon which the 
lamina immediately rests. The lamina is always relatively small, being represented 
in the majority of the traps by a scale or lobe, and it only appears to be an 
appendage of the large expanded and hollowed-out petiole. In many pitcher- 
plants the little lamina looks like a lid placed over the orifice to the pitfall, as, 
for instance, is shown in the illustration (fig. 21°), whilst in others (Nepenthes 
ampullaria and N. vittata) it has the form of a handle or stalk, and serves as a 
place for animals visiting the pitchers to alight upon. 
