74 THE VICTORIAN NATURALIST. 



NOTE ON UTRICULARIA DICHOTOMA. 



By C. a. Topp, M.A. 



{Read before Field Naturalists' Club, 8th February, 18 36. 



Ik August, 1884, I read a paper on " Some Observations on the 

 Genus Utricalaria," a small group of flowering plants remarkable 

 for their carnivorous habits. My remarks were chiefly limited to 

 the species U. hiterijlora, the only one whose utricles I had seen in 

 a fresh state. This spring I obtained specimens of the larger species, 

 U. dichotoma, and I propose to give a short account of my observ- 

 ations of this plant. U. dichotoma, (Labill..) when in flower forms 

 a pretty plant, bearing two or three bright lilac flowers on a slender 

 stalk from to 12 inches long. The radical leaves are in general 

 not above ^ inch in length, and are hardly noticeable; the plants 

 usually grow in considerable numbers together in swampy patches, 

 and flower in October and Noveniber. Those which I have examined 

 were found by Mr. F. G. A. Barnard, at Ringwood. I have also 

 found them at Caulfield and Oakleigh. 



The utricles, which are tlie organs for entrapping tlie larvae of 

 insects and small crustaceans, are attached by slender footstalks to 

 the petioles of the leaves, the petioles and utricles being underground. 

 Each utricle is nearly gloliular, and is from 1-12 to 1-10 inch in 

 diameter. One surface is somewhat flattened, this may be called 

 the ventral aspect, at the base of this is the fof)tstalk, and at the 

 top a projection, called by Darwin from its resemblance to that 

 organ in insects, an antenna; tliis is a slender process, about half 

 the diameter in length, ending in a forked hair. In its natural 

 position it appears to be curved over the ventral surface of the 

 bladder, probably to prevent the entrance to the I ladder from being 

 choked with sand. Underneath this process is an orifice or mouth 

 leading into the interior of the utricle, and between tlie footstalk 

 and this opening, the surface of the utricle is covered with slender 

 multicellular hairs. The outer surface of the whole bladder is formed 

 of polygonal transparent cells, studded over at intervals with small 

 globular projecting glandular cells. A spiral vessel continuous with 

 that of the footstalk, runs round the dorsal surface of the utricle 

 to the commencement of the antenna. I'he opening into the utricle 

 is protected by a deep collar, which is readily seen through the 

 transparent cell wall; this collar is formed of closely set oblong cells 

 filled with dark granular matter. 



The interior of the utricles is closely beset with quadritid glands 

 formed of four elongated conical cells on a short footstalk, similar to 

 those shown in figure 28^ " Darwin's Insectivorous Plants," as 

 found in U. montana. The conical cells are only about 1-500 inch 

 long, and it is singular that they are actually smaller than those 



