THE SEED. 



59 



177. The hilum is the scar or mark left in the testa of the 

 seed by its separation from the funiculus. It is commonly called 

 the eye^ as in the Bean. In orthotropous and campylotropous 

 seeds, the hilum corresponds with the chalaza ( 140). In other 

 conditions it does not ; and the raphe ( 141) extends between 

 the two points, as in the ovules. The foramen of the ovule is 

 closed up in the seed, leaving a slight mark the micropyle. 



204 



205 206 



237 



212 



213 



Reed of Water Lily (Nymphaea), enlarged section; aft., nlbnmen; rt, the embryo contained in tl.e 

 embryo-sac; *, tejrmen; />, testa; r, raphe; ar, aril; m, orifice; /, funiculus. 203, Seed of Bean. 204, 

 Same, one cotyledon with the leafy embryo. 205, Seed of Apple. 206, One cotyledon showing the 

 raphe and embryo. 207, Fruit of Mirabilis; embryo coiled into a ring. 208, Onion; embryo coiled. 

 209, Convolvulus; leafy embryo folded. 210, Embryo of Cuscuta. 211, Typha. 212. Ranunculus. 

 213, Hop. 



178. The seed-kernel may consist of two parts, the embryo 

 and albumen, or of the embryo only. In the former case the 

 seeds are albuminous in the latter, exalbuminous j a distinction 

 of great importance in systematic botany. 



179. The albumen is a starchy or farinaceous substance 

 accompanying the embryo and serving as its first nourishment 

 in germination. Its qualities are wholesome and nutritious, 

 even in poisonous plants. Its quantity, when compared with 

 the embryo, varies in every possible degree ; being excessive 

 (Ranunctilaceae), or about equal (Violacese), or scanty (Convol 

 vulaceae), or none at all (Leguminosoe). In texture it is mealy 

 in Wheat, mucilaginous in Mallows, oily in Ricinus, horny in 

 Coffee, ruminated in Nutmeg and Pawpaw, ivory-like in the 

 Ivory-palm (Phytelephas), fibrous in Cocoanut, where it is also 

 hollow, enclosing the milk. 



180. The embryo is an organized body, the rudiment of 

 the future plant, consisting of root (radicle), stem-bud (plumule) t 



