8 



PLANT PROPAGATION 



germinate. In Lima bean it is seen close to the hilum. 



13. The hilum of a seed is the scar left by the separa- 

 tion of the seed from the placenta of the ovary. 



14. The embryo usually consists of three parts; cotyle- 

 dons or seed leaves; plumule or rudimentary stem with 

 its attached leaves between the cotyledons ; and the cau- 

 licle or first internode or length between joints of the 

 stem below the cotyledons and above the true root. 



15. The number of cotyledons is used to divide plants 

 into three classes: Alouocotylcdonous, or plants with only 

 one cotyledon (asparagus, lily and grasses such as corn 

 and bamboo) ; dicotyledonous, plants with two cotyledons 

 (radish, marigold, dandelion) ; and polycotylcdonoiis, 

 plants with more than two cotyledons (pine, spruce.) 



16. Farm and garden crops are almost all grown from 

 seeds. Irish potatoes and sugar 

 cane produce more or less seed, 

 but this is not used except to 

 develop new varieties. Jeru- 

 salem artichoke, sweet potato, 

 tarragon and horseradish (17) 

 no longer naturally produce 

 seed, so must be propagated bv 

 asexual methods. Tree and 

 small fruits do not come true 

 to name or variety from seed ; 



holes; below, the Seedlings are almost alwavs 



dibbling-in seedlings. • r 



mtenor m some way or waj-s 

 to varieties propagated asexually. 



17. Horseradish from seed.— A Hungarian experimenter has pro- 

 duced horseradish seed by ringing. Two types of plants were pro- 

 duced. Had their origin not been known they would hardly ha\e 

 been classed as the same species. Hence the author concludes that 

 horseradish is only a hybrid and that the contrasting forms result 

 from breaking this hybrid into its original types. 



18. The essential organs of flowers are the pistils which 

 contain the ovules or unfertilized and undeveloped 

 "eggs," and the stamens which contain in their anthers 



