CH. I.] SOWING. 43 



motion their elaborating powers for the nutriment of 

 the radicle and plantlet, for if thej are removed, or 

 if thev have been injured bv insects, the seed does 

 not germinate, and if they are removed even after 

 the radicle is developed into a root, the plants 

 vegetation ceases. 



No sooner has the radicle escaped from the seed's 

 integument, tlian it immediately proceeds to elongate 

 in the dii'ection of the matters most promotive of the 

 future plant s growth. If the seeds of carrots, pars- ■■ 

 nips, beets, and other fusiform-rooted plants are 

 sown in a soil with its surface richly manured, and its 

 subsoil deficient in decomposing organic matters, 

 the plants will have forked and abundant lateral 

 roots, keeping within the fertile surface soil. On the 

 other hand, if the surface stratum is only moderately 

 rich, but some manure is trenched in with the bottom 

 spit so as to be about sixteen inches below the ,seed, 

 the roots \vill strike down straight to this superior 

 source of nutriment. 



From the same cause the roots of orchidaceous 

 plants, grown upon wood only partially charred, will be 

 found to have their roots clamber up, and around, and 

 along the wood, but always directing their course most 

 numerously towards the charred portion. Again, 

 the seeds of the misletoe placed upon the under 

 surface of a bough, always have their radicles grow 

 upwai'ds to penetrate the bark, and thus secure to 



