CHAPTER II 

 PROPAGATION BY MEANS OF. SEEDS AND SPORES 



THE seed is the epitome of the plant, the result of the final 

 process of the plant's activity. To germinate, to vegetate, 

 to build its characteristic structure, to flower, to seed or to 

 spore, this is the cycle of the plant. Some plants die 

 when seeding is accomplished, whether the epoch transpires 

 within one twelvemonth as with the pigweed or within a 

 score of years or a century as with certain agaves. Other 

 plants flower and seed perennially for two or three years 

 as with red clover and hollyhock, or year after year indefi- 

 nitely as with the lilac and the forest trees. Yet whatever 

 the span, the seed or the spore completes a cycle, that new 

 individuals may be born to continue the life of the species. 



The characteristic propagative body of the flowering plants 

 (known also as phenogams and spermatophytes) is the seed. 

 It is the result of sexual union in the flower; it comprises an 

 embryo contained within integuments, and usually a supply 

 of stored food to support the first growth of the plantlet. The 

 characteristic propagative body of the flowerless plants (known 

 also as cryptogams) is the spore; it contains no embryo; it 

 may be only a single cell ; some spores are the result of sexual 

 union and others are not. The spore-bearing plants, when 

 the term is used in this sense, are the ferns and their allies, the 

 mosses, fungi, algse and lower forms. Germination is the act 

 or process by means of which a seed or spore gives rise to a new 

 plant. Germination is complete when the plantlet has ex- 



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