K.—BOTANY 195 
Because of this, my raising U. caerulea to separate dignity has a 
secondary purpose, namely, to point out that the general form of the 
trap assimilates it to the trap of the type under which U. reniformis, 
U. vulgaris, etc., may be subsumed. A mere examination of the form 
of the trap would readily lead one to suppose that U. cerulea and U. 
reniformis are alike. ‘The former has single and bifid absorbing trichomes, 
the latter quadrifid. 
The trap in U. cewrulea is rounded in lateral view, and the slightly 
protruding curved overhang is provided with two rather long, curved 
antennz. ‘The threshold is broad and its inner region is uptilted, in 
some species in a marked degree. In sagittal section, the curvatures 
of the threshold are singularly graceful. ‘The door, also as seen in sagittal 
section, curves downward and backward, the edge resting on the middle 
zone of the threshold, in front of the uptilted inner zone. The upper 
outer surface of the door is beset with a good number of clavate trichomes, 
somewhat longer above than below, and differing only slightly in form 
from those of U. capensis, etc., and doubtless serving the same function— 
probably contributing to the attraction of prey or facilitating the actuation 
of the trap, which, without doubt, consists in causing an initial dent in 
the upper region of the door, the pressure of water taking advantage of 
the failure of resistance thus started. In structure, the upper part of 
the door has a thin outer course and a thick inner course of cells, the same 
structure extending round the sides as far as the door edge. This is 
the outer hinge area. The middle piece is thicker and is of cell courses 
of equal thickness, with thick outer walls. This is compressed downward 
on the threshold by the lateral hinge areas, as in U. cornuta. 
Plants with traps of this type seem to be confined to the Old World. 
They range from very small delicate plants to rather large ones—e.g. 
U. equiseticaulis Blatter and McCann has leaves up to 9 cm. long; U. 
prehensilis has long twining scapes bearing its yellow flowers. They are 
all ‘ terrestrial,’ the typical habitat being wet, often muddy, places, the 
plants forming dense green mats. The leaves scarcely rise above the 
surface ; when large they lie on the mud, the under surface of the leaves 
bearing traps, often plugged full of the fine sediment and rendered 
incapable of action. 
Of the species fitting the type U. cwrulea, there are known to me 
U. Gibbsie, U. albo-cerulea, U. affinis, U. uliginosa, U. bifida and U. 
reticulata, several Ceylonese species only tentatively named (Simpson 
9484, 9487, 9492, 9517, 9580, 9581, 9856, 9971, 9972) kindly sent 
me by Mr. Simpson. I am further indebted to Mr. R. E. Holttum, 
Mr. 'T. Ekambaram, and Mr. E, Blatter for Malayan and Indian collections. 
The structure of the door is much as in U. cornuta, being as follows: 
the upper half and lateral hinges are composed of a thin outer and 
thicker inner course of cells, the whole effecting outward bending but 
capable of inward swing ; and, surrounded by the lateral areas, is the 
middle piece, appearing as the lower half of the door in sagittal section. 
It is thicker and more rigid and is of cell courses of equal thickness and 
with thick outer walls (cf. Figs. 6-8). 
The pressures inherent in the door itself become apparent when a 
