Francis E. Lloyd — 216 — Carnivorous Plants 



Old and New Worlds, with northward extensions along the Atlantic 

 coast, through Central America, and along the Pacific Coast of Asia. 

 These include a considerable number of distinct types, some of which 

 are pecuHar to America, others to the Old World, and still others 

 common to both (£/. suhulata). They are to be found also in Aus- 

 tralasia. 



So far as is known, Utricularia is not found on oceanic islands. 



Embryology. — The embryological story of Utricularia has not yet 

 been worked out in its fullness, but certain striking features have 

 been observed and have been recorded by Lang, Merl (Genlisea), 

 Merz, and Wylie and Yocom. Merz pointed out that the vascular 

 tissues supplying the large placenta end there and do not enter the 

 funicles of the ovules. As a compensation for this, it would appear, 

 special masses of nutritive tissue arise in the chalaza and in the pla- 

 centa {Utricularia vulgaris, etc.) or what amounts to the same thing, 

 in a "funicular hump" (to quote Wylie) (Poly pomp holy x Lehm.). 

 These islands of food materials are made use of for the embryo by 

 the penetration into them of peculiar haustorial extensions of the 

 endosperm. Transitory starch appears in these haustoria. These nu- 

 tritive masses are finally cut off from the ovule, as the embryo ap- 

 proaches maturity, by the development of diaphragms of suberized 

 cells. Since according to Merz the end of the suspensor extends 

 into the placental nutritive tissue, this is cut ofT at the same time. 

 Wylie and Yocom do not support this. In the related Genlisea, 

 nutritive islands occur entirely within the ovule (Merl). 



The ovule has but a single integument, which is common enough 

 among the sympetalae, from the outer cell course of which a thin 

 testa is derived. The tegmen, membranous and delicate, may repre- 

 sent the remaining tissue of the integument, since the nucellus is 

 absorbed (Merz). The mature embryo has neither root nor punctum 

 vegetationis (Merl, Lloyd). 



Seed, embryo and seedling. — The seeds, in most cases, develop 

 on a large globular, central placenta, and are crowded suf^ciently 

 in some species so that by mutual compression, they become angu- 

 lar, approximately hexagonal, with fiattish outer chalazal and inner 

 micropylar surfaces, the latter the smaller (Warming, Wylee). The 

 planes of the sides radiate as if from the center of the placenta {U. 

 vulgaris, U. resupinata), or the ovules overlap and become winged 

 with circular wings {U. oligosperma, U. exolcta) the whole dished 

 into a concavo-convex lens shape. In other species, chiefly terres- 

 trial, the seeds are minute (down to 0.2 mm. in diam.) and globular 

 or oval, occasionally lobulate {U. reniformis, U. Dusenii, U. pur- 

 purea) or have polar clusters of trichomes {U. brachiata) (Compton) 

 or scattered glochidia covering one end {U. orbiculata). 



The testa is composed of an epidermis of darkened (reddish or 

 brown), relatively large cells with their inner and radial walls thick- 

 ened, the outer thin and collapsed in maturity. Their shape varies 

 from round angular to elongate, many and relatively small or few 

 and relatively large. In a few instances they become mucilaginous 

 when wet, in species which grow with the vegetative parts submersed 

 and attached to a stony substrate in running water {U. rigida, 



