THE SEED. 



CHAPTER XIV. 



THE SEED. 



582. THE SEED is the perfected ovule, having an embryo formed with- 

 in, which is the rudiment of a new plant similar in all respects to the 

 original. The seed consists of a nucleus or kernel invested with 



583. THE INTEGUMENTS OR COVERINGS. The outer covering is the 

 testa, the inner the legmen, as in the ovule. The latter is thin and 

 delicate, often indistinguishable from the testa. 



456 



457 463 



453 



Seed of Water-Lily (Nymphaea), enlarged section; ., albumen; a, the embryo contained 

 in the embryo-sac ; *, secumline or tegmen; p, pritnine or testa ; >-, raphe , ar, aril; m, mi- 

 cropyle ; ./; funiculus. 463. Seed of Uean. 464, Same, one cotyledon with the leafy embryo. 

 461, Seed of Apple. 462, One cotyledon showing the raphe and embryo. 460, Fruit of Mirabi- 

 lis; embryo coiled into a ring. 454, Onion ; embryo coiled. 455, Convolvulus; leafy embryo 

 folded. 456, Embryo of Cuscuta. 45T, Typha. 45$, fianuneuius. 459, Hop. 



584. THE TESTA is either membranous (papery), coriaceous (leath- 

 ery), crustaceous (horny), bony, woody, or fleshy. Its surface is gen- 

 erally smooth, etc. (118, ). 



585. THE COMA MUST NOT BE COXFOUN'DED WITH the pappus, which is a modi- 

 fication of the calyx, appended to the pericarp, and not to the seed, as in the ache- 

 nia of the thistle, dandelion, and other Composite. Its intention in the economy 

 of the plant cannot be mistaken, serving like the pappus to secure the dispersion o! 

 the seed, while incidently as it were, in the case of the cotton-seed, it furnishes 

 clothing and employment to a large portion of the human race. 



586. THE ARIL is an occasional appendage, partially or wholly in- 

 vesting the seed. It originates after fertilization, at or near the hilum, 

 where the seed is attached to its stalk (funiculus). Fine examples are 

 seen in the gashed covering of the nutmeg, called mace, and in the scar- 

 let coat of the seed of staff-tree. In the seed of Polygala, etc., it is but 

 a small scale, entire or 2-cleft, called caruncle. 



