The traps of Utricularia baoulaensis A. Chev., U. bifida L., U. graminifolia Vahl, U. kumaonesis Oliver, U. scandens Benj. and U. squamosa Wt. are studied.
The mouth of the trap has a distinct rim and is lateral, terminal or basal. The antennae or appendages on the dorsal side of the mouth are forked and not branched further in U. bifida, U. graminifolia, U. scandens and U. squamosa; in U. baouleensis they are further branched into two or three branchlets and in U. kumaonensis the appendages ramify further into uniseriate filaments bearing stalked, globose glands at their tips. The wall of the trap is 2-layered. There are bifid digestive glands along the inner layer of the wall in all the species, except U. kumaonensis where only quadrifid glands are seen. The mouth is guarded by a complicated trap mechanism, consisting of the door, velum and threshold.