387 



Such an increased supply of plastic food material is present, if some 

 disturbance in the normal economy of the plant arises, due to the removal 

 of certain centers of consumption. Goitre gnarl formation arises from the 

 removal of branches necessitated by trimming the trunks and various other 

 kinds of pruning, ^^'e find striking examples of this in lindens, poplars, 

 maples, etc., planted along streets ; in an ever-increasing accumulation of 

 buds at the places where branches have been removed. If such gnarl accum- 

 uations occur at especially preferred places, well suited for the work of 

 assimilation, some shoots from these gnarls gain the upperhand and ap- 

 proximate water sprouts. 



c. Effect of an Excess of Nitrogen. 



As seen already, a disturbance in the formal development of the plant 

 body by a local accumulation of the prepared building materials is, to be 

 sure, of interest scientifically but has no great disadvantage agriculturally. 

 Indeed, we actually find that the cultivation of such formal variations, as 

 doubled flowers, is often intentionally increased. The conditions are very 

 different, however, if the material processes are unequally affected by the 

 raw materials. Here the question of fertilization comes primarily under 

 consideration and disturbances are especially involved which are produced 

 by an excess of nitrogen and an unequal increase of the supply of potassium. 



We have already mentioned the fact that the soil will be injuriously 

 influenced physically by an over-abundant supply of soluble fertilizing salts. 

 Even if the salts keep the soil damper, as long as sufficient atmospheric 

 precipitation is present, yet they form a constant menace for the plants in 

 time of drought, because a too highly concentrated soil solution may easily 

 be produced, making more difficult the passage of the water into the plant 

 roots^. This cannot fail to have some effect on the development of the 

 plant. Gerneck's^ work throws some light on this subject. He observed in 

 Triticum that root hairs were formed more abundantly if Ca(NO:;)o was 

 added than if KNO, was used. In feeding with nitrates, the blades and 

 ears developed late, while, with chlorid and phosphate fertilization, they 

 appeared early. With the latter method, the root cells appeared to be more 

 thickened than with the former, in which the epidermal cells and the leaf 

 schlerenchyma were also the least lignified. 



We will now discuss a few special cases. 



Over-Fertilized Seed. 



The erroneous theory that plants can be brought to unbounded per- 

 fection by abundant fertilization has given rise to an endeavor to give seeds 

 additional help by fertilizing them at the time of sowing. The seeds were 

 either "candied," i. e. coated with a crust of nutrients, or they were soaked 



1 "Wollny, K, ITntersuchungen liber den Einfluss der Salze auf die Boden- 

 feuchtigkeit. Vierteljahrsschr. d. Bayer. Landwirtschaftsrates 1899. Supplement 

 p. 437. 



- Gerneck, R., tjber die Bedeutung- anorg-anischer Salze fur die Entwicklung 

 und den Bau der hoheren Pflanzen. Gottinger Dissertation, cit. Just, Bot. Jahresber. 

 1902, II, p. 301. 



