Francis E. Lloyd — 222 — Carnivorous Plants 



In the species U. oligosperma there is a pronounced dimorphism 

 of leaves, each kind occurring on separate branches. Those of one 

 kind bear none, or very few poorly developed traps. They are finely 

 divided with very long terminal divisions in the form of fiat, ensi- 

 form divisions, and are very crowded, so that the leafy branches 

 appear as dense tufts strongly contrasted with those which bear the 

 second kind of leaves which are trap bearing. The traps are very 

 numerous and crowded, and the leaves which bear them have only 

 a single lobe, whose divisions all He in the plane of the axis which 

 bears them. 



The leaves in this and similar species {e.g. U. mixta) are provided 

 on one side only with a small fohose appendage consisting of about 

 four radiating accuminate members each bearing a trap, the whole 

 having a stipulate appearance (2j — 3). These may be similar to 

 the minute axillary shoots mentioned by Pringsheim in U. vulgaris 

 {21 — 10), different only in position. 



A pair of similar appendages (we may call them tentatively dwarf 

 shoots) occurs also at the sides of the base of the air shoot, but here 

 they often have more divisions, each carrying a trap (23 — 2, 6), 

 They are found also in U. mixta. To the unaided eye in such cases 

 there appears at the base of the air shoot a tight grape-like cluster 

 of as many as a dozen, or as few as two to four traps. Without 

 careful examination it would seem as if the air shoot were supplied 

 with stipules, but the organs in question arise directly from the axis. 

 They, however, derive their vascular strands as branches from the 

 main strand entering the air shoot, though exceptions have been 

 noted. So far as I am aware these pecuHar dwarf leaves are to be 

 found only on those species which have strap-shaped stolons, the 

 greater longitudinal plane being vertical, the upper edge somewhat 

 narrower than the lower. They cannot readily be homologized with 

 the auricles of some species because of the distinct origin from the 

 stolon. 



A large number of species of the U. vulgaris type {U. exoleta, 

 emarginata, gibba, cymbantha, etc.), plants with thread-Kke stolons, 

 have leaves which may be no more than a single fork, two slender 

 segments arising from the base, only the lower one bearing a single 

 trap (27 — 17, 18); or they may be variously more complex, but 

 always much simpler than in U. vtdgaris. 



Branching; origin of the inflorescence. — It was quite apparent to 

 the earlier observers (Irmisch 1858; Buchenau 1865) that branch- 

 ing in Utricularia does not follow a pattern common to the flower- 

 ing plants. The observations of these students, with those of 

 Pringsheim (1869) and Goebel (1891), afford the available basis for 

 description to which my own studies have been added. From these 

 there emerges in fairly clear form the pattern peculiar to these very 

 aberrant organisms. We consider U. vulgaris which Pringsheim 

 studied developmentally, in contrast with Irmisch and Buchenau 

 who examined only the mature condition. 



U. vulgaris. — The growing point (2/ — 8) of the horizontal shoot 

 shows upward circination (Pringsheim, Goebel) and that (i) a row 

 of peculiar branches arises in a line on the upper surface of the stolon 



