PLANTS AND THEIR SEED 33 



PART II.-PLANT8 



( BAPTEB \ I. I'i.ants \m. Their Seed 



33. Annuals, Biennials, and Perennials. — Most of the 

 plants cultivated on the farm art- grown from seed, a 



row from cuttings, and a few from roots, but the 

 more important farm crop* all grow from seed. Plants 

 are often diTided into three groups — annuals, biennials, 

 and perennials. These words refer to the length of the 

 plant's life. Annuals are plants living about one year; 

 i in ANiALS, plants living about two years; and peren- 

 nials, plants which live on year after year for an in- 

 definite period. Annuals grow rapidly to their full 



produce a crop of seed, and die all in about one 

 year's time Biennials often reach their full size in one 



l>ut do not produce seed till the second year. After 

 producing a crop of seed they also die. These two 

 classes of plants produce only one crop of seed. Peren- 

 nials have no fixed lifetime — some such as oak trees live 

 to be hundreds of years old, others live only a few 

 years. Host perennials produce seed each year; others 

 onljf at longer intervals. 



34. Seed. — Most farm crops grow from seed; corn, 

 oats, wheat, cotton, rice, and tobacco all come from 

 the planting of seed. Each crop produces but one kind 

 of seed, and this seed when planted in turn produces 



3 



