AGEICULTURAL. BOTANY. 127 



from one-third to one-balf of the total organic matter of the plants had been 

 accumulated. With the development of the heads there was a translocation of 

 the plastic material, first from the leaves and then from the stems to the 

 heads. The growth of the vegetative organs was completed before the forma- 

 tion of the flower heads. In the ripe heads the seeds constituted one-half of the 

 dry weight of the head. 



It was found that the total nitrogen, the albuminoid nitrogen, and the nitro- 

 gen occuia"ing in asparagin and organic bases varied during the difl'erent stages 

 of growth, the nitrogen being mostly in the leaves during the first half of the 

 growing period, while in the second half it was found in the flower head. The 

 formation of asparagin took place to a greater extent during the first stages 

 of the formation of the head, when the decomposition of the albuminoid nitro- 

 gen was rapidly taking place. 



The mineral matter was found most abundant in the leaves, and it was present 

 in greatest quantity during the period of formation and flowering of the heads. 

 In the stems the ash content was the highest during the first half of develop- 

 ment, while in the heads it was greatest during flowering. 



In comparing the sunflower with other plants it was found that the sun- 

 flower needs more nutritive material than cereals or clover, but less organic 

 matter than either. 



In regard to the water requirements of the sunflower, these were found to be 

 the greatest from the time of sprouting to the development of the sixth or 

 eighth leaf, after which, by the deep penetration of the root system, the plant 

 can thrive in relatively dry soils. 



The assimilation of phosphoric acid by plants, I. Pouget and D. Shushak 

 (Zliur. Omiin. Agvon. {Rhuh. Jour. E.rpt. JmikIic), 11 (1910), No. 6, pp. 825- 

 831). — Experiments are reported on the assimilation of phosphoric acid by 

 wheat seedlings grown in water cultures to which different amounts of potassium 

 phosphate were so added as to make the quantity of phosphoric acid vary from 

 0.05 to 4 mg. per liter of solution. 



For the concentrations varying from 1.1 to 4 mg. the assimilation of phos- 

 phoric acid was in direct proportion to the strength of the solution. In con- 

 centrations of 1 to 0.137 mg. no direct relation was observed to exist between 

 the taking up of the phosphoric acid and the strength of the solution. 



No relation was found to exist between the amount of water evaporated by 

 the plant and the amount of phosphoric acid taken up by it, and under the con- 

 ditions of the experiment phosphoric acid was taken from the solution more 

 rapidly than the water, the concentration being proportionately reduced, except 

 that where the weaker solutions were employed, as from 0.1 to 0.05 mg., there 

 appeared to be an increase in the amount of phosphoric acid in the solution. 

 This was believed to be due to an exudation from the roots, the phosphoric 

 acid probably existing in the plant in the form of a complex organic compound. 



The lime requirements of plants, N. I. Konovalov (Dnevn. XII. S"iezda 

 Russ. Est.-Isp. i Vrach [Moscow], 1910, No. 9, p. 391; abs. in Zhur. Opytn. 

 Agron. {Russ. Jour. Expt. Landio.), 11 (1910), No. 1, pp. 107, 108). — The results 

 of the author's investigations indicate that the development of millet, oats, 

 wheat, lupines, etc., is dependent on the amount of calcium present in the 

 nutrient solution. He states that the theory of Loew, while ascribing essential 

 importance to the ratios of calcium to magnesium, does not give sufficient 

 attention to the amounts of these substances required by plants. 



The influence of manganese on the development of Aspergillus niger, 

 G. Bertrand and M. Javillier (Com.pt. Rend. Acad. 8ci. [Paris], 152 (1911), 

 No. 4> PP' 225-228), — ^A preliminary report is given of investigations with 



