ORGANS OF REPRODUCTION. 



59 



inner skin of an egg ; but in tlie fir and cycad families 

 the ovule is destitute of a seed coat, hence these plants 

 are called gymnosperms, that is, naked seeds. The ovule 

 contains the embryo only, or it consists of soft or hard 

 matter called albumen, with the embryo embedded in it. 

 This matter is homogeneous, and abounds in wheat and 

 barley, becoming the farinaceous part, as flour and all 

 corn meals ; it is also plentiful in palms, as for example 

 the white of the cocoa-nut. Its presence or absence 

 characterizes many natural families. Seeds containing 

 it are called albuminous, and those without it exalbu- 

 minous; the pea and bean are examples of the latter, the 

 part eaten being the seed leaves of the embryo. 



Germination of Seed and Young Plant. — I have now 

 described the principal forms of the various parts of a 

 plant, from the root upwards to the perfect seed, within 

 which by the power of nature's act, an embryo or germ, 

 endowed with the vital principle of vegetable life, has 

 been generated, so that on the seed falling to the earth 

 and becoming influenced by heat and moisture, the vital 

 power of the embryo is excited, and immediately com- 

 mences the growth of a plant like unto its parent. 



In order to observe the process of germination, place a 

 few seeds of corn, onion, radish, mustard, pea, bean, &c., 

 in a shallow vessel on wet brown paper, or other substance 

 retentive of moisture, covering them with the same kind 

 of material, and placing them in a moderately warm place 

 in the dark. After a short time a change will take place, 

 being first apparent by the swelling of the seeds. In the 

 pea and bean the coat bursts, and two lobes are seen to 

 open, and at their base or point of union is seated a small 

 body called the plumule (the embryo bud of the future 

 plant), which lengthens upwards and forms the stem ; 



