32 



CLOSSARV or 



Nucleus : tlie body of the ovule witliin the coats (Fig. 172, A:). 

 Embkyo-sac : tlie L-irue cell in the nucleus in which the young 



plant is cleveloi)ed (Fig. 1T2, em). 

 Chalaza : the portion where the two coats are blended 



together (Fig. 172, c). 



Kinds of Ovule. 



ORTHOTKOrous : wiieu the ovule is erect, and the uiicropyle is 

 as far as possible from the funicidus or point of attacli- 

 ment (Fig. 172). 



Anatropous : when the ovvtle is completelj^ inverted or bent 

 upon itself so as to bring the niicroj)) le close to the jwint 

 of attachment (Fig. 17o). In this case the funiculus 

 becomes fused with the primine on one side, forming the 

 raphe (Fig. 1713, r). 



Campvlotropous : when the ovule is half bent over (Fig. 174). 



Fertilization. 



Ovules are converted into seeds by the action of pollen upon 

 them. Pollen grains fall upon the stigma which is moist 

 and retains them. The grains begin to grow as shown 

 in Fig. 150, tile inner coat being protr tided as a slender 

 tube which makes its way down throtigh the stjde into 

 the ovary, and then through the micropyle of the ovule, 

 finally attaching itself to the stirface of the embrj^o-sac, 

 and carrying the contents of the pollen-grain with it. 

 Presently' growth begins inside the embryo-sac, and soon 

 the embryo is formed, ^t is the presence of the embrj'o 

 which marks the distinction between an ovide and a seedy 



In most cases the ovule is. fertilized by pollen brought 

 from another flower of the same species (cross-fertiliza- 

 tion), because very commonlj^ the pollen of its own flower 

 is ready either too soon or too late to be of tise ; that is, 

 the pollen and the stigma in the same flower do not com- 

 monly mature at the same time. Plants are 



EnlomopJiilous, when the3' depend upon insects to 

 carry the pollen from flower to flower, and 



Anamophilous, wdien this service is performed hy the 

 wind. 



THE FRUIT. 

 Definition. 



The friiit^ is the ripjened jiistil together with any otht'r pait, 

 such as the calyx or receptacle, whic h ma y be adherent 

 to it. If there are no such adherent parts the fruit is a 

 true frxiit, consisting wholly of the ripened ovary with 

 the seeds ; otherwi.se it is n jisciulocarp or spurious fruit, 

 as in Ajiple, Strawberry and Jiose. 



Fisr. 173. 



Fig-. 174. 



