16 



SEEDS AND SEEDLINGS 



and texture approaches nearer and nearer to its final con- 

 dition of fruit (Figs. 2, 3). 



2. The seed rudiments meanwhile undergo fundamen- 

 tal changes : the embryonic plants are formed, seed coats 



3. a, the fruit, or matured form of the central organ of the flower 

 (Fig. 1), cut across to show the seeds ; b, a seed, magnified; c, a 

 section of the seed ; cl, the embryo removed from the seed. 



develop, fitted to secure the dispersal of the seeds far and 

 wide, or to protect the embryo, and a store of food for 

 rearing the young plant to a certain stage is provided 

 (Fig. 3). 



3. At length, when the seed is fully ready for its 

 mission, the now ripened fruit falls to the ground and 

 decays, liberating the seeds, or is borne away by currents 

 of wind or water, or by animals. Or, remaining on its stem, 

 it either opens (Fig. 3), allowing the seeds to be scattered 



by a variety of agencies, or in a 

 number of cases bursts, forcibly 

 ejecting the seeds from their 

 receptacle. 



4. The primitive plant, or em- 

 hr^o, inclosed in the seed, may be 

 so rudimentary that it shows no 

 distinction of organs. Such a case 

 is furnished by Orchids, epiphyt- 

 ic^ upon trees in tropical forests. 

 Their flowers are often large ; but 

 the extremely numerous seeds are 

 of the smallest size, and of the 



1 Epiphytes grow upon, but derive no sustenance from, other plants. 

 Parasites live at the expense of their hosts. 



Seed of an Orchid, with 

 loose, buoyant coat, and 

 a rudimentary embryo 

 (magnified) . 



