18 



SEEDS AyO SEEDLIXGS 



6. Embryo o( the Yel- 

 low Pond Lily 

 (magnified). 



the cotyledons, with several of the first leaves which it 

 will bear (Fig. 6). This bud of the ascending axis, already 

 developed in the seed, is the plumule. 

 lu the Bean and similar strong euibiyos 

 the leaves of the plumule are already 

 perfect as concerns outline, veining, 

 and so on, and need only to gaiii green 

 color and a larger size to become use- 

 ful to the seedling as foliage. These 

 plants, therefore, ver_y soon after coming out of the 

 ground are found actively acquiring the means of further 

 growth, while still using nourishment _ 



inherited from the parent })lant. 



10. Food. — Along with the incipient 

 plant is sent a store of food in a form 

 easily used, with which its start in 



an independent ca- 

 reer will Ijc made. 

 The amount is as 

 variable as the size 

 of the embryo it- 

 self. It may be 



relatively very large, as seen in the 

 seed of Actiea (Fig. 7). In Fig. 8 

 the embryo is relatively larger than 



the mass of nutrient material. This 



example prepares us for the condition 



seen in the seed of many families of 



plants, where a supply of nutriment 



separate from the germ itself is never 



developed (Fig. 9). 



11. Food matter external to the 

 embryo is termed aUnimeii, or endo- 

 sperm, and seeds having it are called iilbiniiinous seeds. 

 Those lacking albumen are called exalbuminous. 



12. It will readily be seen in most cases that embryos 

 unfurnished with albumen are not in consequence the 

 worse off. for tliev are of larger size and their tissues are 



8. Seed o£ the Purslane, 

 in section, the em- 

 bryo surroundin):; 

 the reduced albu- 

 men (magnified). 



Section of the ,';eed 

 of Arttva, show- 

 ing the minute 

 embryo and the 

 relatively abui\- 

 dant albumen 

 (magnified). 



9. Exall)uniiuous seed 

 of Gi/nandrop- 

 t<is, in section 

 (magnified). 



