Chapter XIII — 217 — Utricularia, Biovularia 



and probably U. neottioides) . In a very few instances the seed has 

 no hard testa, but simply a thin lax membrane easily torn, and the 

 seed seems to be released by the rotting away of the capsule {Bio- 

 vularia) . 



Embryo. — The embryo is a mass of scarcely differentiated cells 

 containing much starch and oil, and is either bun shaped with a 

 depression at the vegetative pole {U. vulgaris) (Warming) (2/ — 6) 

 or flattened by lateral compression, with the growth pole on its edge 

 {U. emarginata and exoleta) {21 — 7), this position and form being due, 

 according to Merz, to rotation of the embryo-sac and embryo through 

 90 deg. following the abscission of the egg-pole endosperm; or again 

 more or less oval or spindle shaped (a host of species, e.g. U. bifida) 

 (22 — I, 18). In a few there is a depression at the root pole (Poly- 

 pompholyx) {22 — 26). Its structure is very simple: it is a mass 

 of rounded parenchyma clothed with an epidermis, the cells of which 

 covering the growth pole are small, columnar and highly protoplas- 

 mic. The primary organs usually originate at this pole, but may 

 occasionally appear elsewhere {U. bifida) {22 — 19-22). There is an 

 entire absence of a root. Even at maturity the embryo has as yet 

 no lateral organs. Goebel reported them in the embryo of U . or- 

 biculata, but I have failed to find them. In U. reniformis and U. 

 nelumbijolia primary leaves have been seen, and these species may 

 display vivipary (Merl). 



While the growth pole produces lateral organs, two in many cases 

 (cotyledonoids) or various numbers in others, a punctum vcgetationis 

 (the primary primordium of a shoot) is never present in the embryo, 

 nor is ever developed. Shoots when present in the plant are always 

 produced as lateral organs. 



Germination {22 — 1-28). — The events of germination show that 

 there are three types of seedling: (i) a simple, in which there are 

 two cotyledonoids (since one of these is a stolon); and (2) a com- 

 plex, in which there are 6 to 13 (Warming, Jane) cotyledonoids, 

 or indeed only two; and (3) a type in which there are no cotyledonoids 

 at all, with three primary shoots only. The simple type is displayed 

 by all the terrestrial species (so far as known), such as U . capensis, U. 

 bifida, U. monanthos, Polypompholyx, which have been studied. The 

 complex type is seen in U. vulgaris (with many cotyledonoids) and in 

 U. exoleta, U. emarginata etc. (with two cotyledonoids). U. capensis 

 among others has been studied by myself (19376). The seed is minute 

 and oval in shape. From the growth pole emerges at first a leaf 

 followed shortly by a stolon. Between them in the expected position 

 there is no punctum vcgetationis. The leaf extends upwards, the stolon 

 downwards. The first evidence of further growth is the appearance 

 of a trap, on the base of the stolon, a little away from the middle 

 Kne (22 — 14), or rarely, as in U. cleistogama, asymmetrically near the 

 leaf base. At the base of the trap-stalk a bud arises which pro- 

 duces an ascending stolon with more or less crowded leaves. This 

 becomes thicker with upward growth, finally becoming an inverted 

 cone, a protocorm bearing leaves, traps and stolons. Their vascular 

 tissues form within the protocorm a loose stem-Hke structure, similar 

 to that described by Warming for Genlisea and by myself for Poly- 



