XX RUDIMENTS OP BOTANY. 



364. The seed is the ovule arrived at maturity. 



165. It consists of integuments, albumen and embryo ; a naked seed 

 is only found in those rare cases in which the ovule is naked. 



166. The seed proceeds from the placenta, to which it is attached 

 by the funiculus ; sometimes this becomes expanded about the seed into 

 a fleshy body, called the arU. 



167. The scar which indicates the union of the seed with the pla- 

 centa, is called the h'dum or umbilicus. 



168. The integuments are called collectively testa, and consist of 

 membranes resulting from the sacs of the ovule. These membranes 

 are called by various names. 



169. Between the integuments and the embryo of some plants lies a 

 substance called the albumen or perispcrm ; the nature of this is of great 

 importance. 



170. The albumen is sometimes farinaceous, as in the grasses ; cori- 

 aceous and almost cartilaginous, as in many Umbelifene ; ruminated or 

 wrinkled as in Anonacese ; horny as in the coffee-bean ; or thin and 

 membranous, as in many Labiate. 



171. The embryo is the organized body that lies within the seed, 

 which is destined to* become a plant similar in all respects to the pa- 

 rent. It is usually solitary in the seed, but occasionally there are two 

 or several. 



172. The embryo consists of the cotyledons, the radicle, the plumu- 

 la and the neck. 



1 73. The cotyledons represent' the undeveloped leaves. 



174. The pbimula, is what is destined to become the stem, and is 

 therefore a rudimentary leaf-bud. 



175. The radicle is the rudiment of the root, and by germination be- 

 comes the root. 



176. The neck or coUum is the line of separation between the radicle 

 and the portion above it. 



177. The number of cotyledons varies from one to several. 



178. Plants that have but one cotyledon, or if with two, then the 

 cotyledons alternate with each other, are Monocotyledonous. These 

 are also Endogenous plants. 



179. Plants that have two cotyledons placed opposite each other, or 

 a greater number placed in a whorl, are called Dicotyledonous. These 

 are also Exogenous plants. 



180. Plants that have no cotyledons, are said to be Acotyledonous. 

 But this term is only applied to cellular plants, which having no sta- 

 mens and pistils, can have no seed. 



181. When the radicle is so bent that it touches the back of one of 

 the cotyledons, it is said to be dorsal, or the cotyledons incumbent. 



182. When the radicle is applied to the edge or cleft of the cotyle- 

 dons, it is said to be lateral, or the cotyledons accumbcnL 



183. When the seed is called into action, germination takes place 

 .and growth commences. 



