NFAV ORGAN IN SEEDS. Q\5 



ing aftenvard tliroughout the T^hole extent of tliC outer 

 co;it, constitute its vascular organization. 



The second, which I term omphalodes*, i^ an aperture The ompha- 

 placed most commonly in toe centre ot.the Inlum, but 

 sometimes toward one of its extremities, and sometimes it is 

 a lougitndinal cleft extending from one end of it to the 

 other. This organ, wholly negleted by botanists, forms the 

 passage between two other vascular systems; the first of 

 which, that is tlie outermost, after having inosculated with 

 the lips of the hilum of tlie internal membrane, forms its 

 Oi'ganization in the same manner as tliat of the outer coat 

 aJready noticed. In fine, as we observe an oraphalodes on 

 the outer integument, we perceive one on the internal mem- 

 brane, through which the third vascular system passes, con- 

 sisting of the umbilical vessels, by which the embryo was 

 attached to the parent plant previous to its fecundation, 

 a^id for some time afterf . 



The third is the subject of the present inquiry. 



All physiologists are avv;are, that the point by which the Direction of 

 ©vula adhere to the ovaries marks the direction in which tbe ^ ^^ "^'^"^"^ '^' 

 radicle will push forth, and thir. is without exception. For 

 instance in some families of plants, as the dipsacea?, capri- 

 foliacece, and jasminetie, the ovula are ponstantly attached 

 to the sui^nmit of the cavity of the ovaries, and the radicle 

 is superior : in others, as the campanulaceae and composite, 

 tbe point of adhesioa is inferior, and the radicle is the same. 

 Bvit the better to generalize our ideas, let us rather say, that 

 the direction of the embryo is always suboidinate to that of the 



* From the greek o/>ti^aXo5-, the navel, and o^os, a way. 



•f Grew appears to be tlie first, who observed the imnbilical vessels of Umbilical ves- 

 t)ie embryo. Tiiese umbilical vessels, the only ones that deserve the sels. 

 name, constitute the innermost vascular system, which, after having 

 passed the coats of the seed by means of tbe omphalodes, divides into 

 two branches, each of which inosculates with the labes of the embryo, 

 near the point where they unite with the radicle anfi plumula It is to 

 be presumed, that these vessels quit the young plant pretty early; for it 

 js extremely difficult, to find any traces of them in ripe seeds, except in 

 those of some of the coniferous plants, the tropa;olum, and several of 

 ^he legumes, in which the two umbilical cicatricalic are very evident. 



seeds 



