72 PLANT LIFE ON THE FARM. 



Growjth and development may go on together at the 

 same time, as we see in an oak tree, which puts forth its 

 midsummer shoots at the same time that it is ripening 

 its acorns and consolidating the new wood ; but in an 

 herbaceous plant, like the wheat, as development pro- 

 ceeds growth ceases at least, to a great extent. So in 

 the case of such plants as the turnip, the mangel, and 

 the hop, when the plant commences to enter upon the 

 flowering stage, then changes not merely of bnlk, but 

 of outward form, and to some extent of inward construc- 

 tion and chemical composition occur. So, as the soft 

 tissues harden into solid wood by deposit of woody mat- 

 ter in their wood cells, development takes place ; and, as 

 the water and the salts taken up by the roots and the 

 gases inspired by the leaves act and re-act upon one 

 another aided or not, as the case may be, by the agency 

 of light various changes occur which may be included 

 under the head of development. Development, then, is 

 morphological in so far as it relates to the conformation 

 of the plant, chemical or physical in so far as it includes 

 the chemical and physical changes which accompany the 

 passage from the young to the old, from the crude and 

 imperfect to the complete and mature. The conditions 

 which favor development in the sense here understood 

 are thus more or less opposite to those which foster 

 growth. Gardeners recognize this by affording plenty of 

 water and sufficient heat to their plants when growing, 

 and by reducing the amount of water as the plant is about 

 to produce flower, fruit, and seed. They apply liquid 

 manure in the growing stage, but withhold it in the 

 ripening period. They root-prune their fruit trees when 

 growth is too vigorous and fruit production too scanty. 

 They check rampant growth by keeping the roots in 

 small-sized pots. The farmer unfortunately has not the 

 same control over his plants that the gardener has, but 

 he is careful as to the time when he applies manure. He 



