58 THE FRUIT. 



ovule. lu this case the ovule, or seed, is said to be orthotropous (erect), Ex. can- 

 dleberry (Myrica). More generally, however, the funiculus (91) extends beyond 

 the hilum, passing under the integuments partly around the nucleus, before it 

 is joined to it. The point of this final juncture is always the chalaza, and that 

 part of the funiculus which then intervenes between the hilum and the chalaza is 

 called the raphe. This form of the ovule, or seed, is called anatropous (inverted), 

 and is exemplified in the apple. The raphe can, therefore, exist only in the ana- 

 tropous seed, and seiwes to distinguish it. (See Fig. 11 ; No's 8 and 9.) 



122. The Albumen. Next within the integuments, there is a 

 wliite substance called the albumen, consisting cliiefly of starch. 

 It constitutes the chief bulk of some seeds, as maize, wheat, 

 rye, and serves to nourish the embiyo in its nascent state. It 

 abounds chiefly in those seeds wliich have but one cotyledon. 

 It is wholesome and nutritious, even in poisonous plants. The 

 albumen in some seeds is entirely wantuag, particularly in the 

 bean, pea, &c., the nutritious matter being all absorbed in the 

 cotyledon. 



123. The EMBRYO is an organized body, the rudiments of the 

 young plant, situated witliin the integuments. To the growth 

 of this all other parts of the seed are subservient. In some 

 seeds the embiyo is distinctly visible. Ex. bean, Convolvulus. 



124. The embryo is divided into three parts ', the radicle, the 

 plumule, and cotyledon. 



a. The radicle is the descending part of the embryo, destined 

 to form the root (radix). In respect to position, it always points 

 towards the foramen. 



h. The PLUMULE is the ascending part of the embiyo, or the 

 rudiment of the ascending axis of the future plant. It is usually 

 directed towards the chalaza. 



125. The COTYLEDON is the bulky, porous, and farinaceous 

 part of seeds, destined to form the first or seminal leaves of the 

 young plant, as well as to afford nourishment to the plumule 

 and radicle, before they can obtain it from the earth. In the 

 bean, squash, cucumber, and most other plants, the cotyledons 

 are conspicuous in rising above the gi'ound. 



a. The number of cotyledons is variable ; and upon this cir- 

 cumstance is founded the most important and distinct division 

 of the Ph^enogamia, or flowering plants. 



126. Monocotyledonous plants are those whose seeds have but one cotyledon, 



