AGRICULTURAL BOTANY. 825 



least 14 species, none of tliem showed any power of assimilating free nitrogen 

 when grown in nitrogen-free media under the conditions of the experiment. The 

 S'pecies of Zdyceliophthora and probably of Fusarium also showed no power of 

 assimilating free nitrogen even when grown in nitrogen-containing media. My- 

 celiophthora when grown in a nitrogen-containing solution assimilated different 

 proportions of nitrogen. dei>ending on the concentration of the nitrogen compound. 

 The amount of combined nitrogen taken up from the air by cultures standing 

 exposed did not seem to be sufficient to make any appreciable difference in their 

 nitrogen content, either when in nitrogen-free or in nitrogen-containing media. 

 The fungi studied did not seem to be able to use nitrogen in all its forms. The 

 Kjeldahl method of analysis was found to be capable of a degree of accuracy 

 which reduced the limit of error to very nearly 0.1 mg. for each determination 

 where small quantities of nitrogen were used, and 0.3 mg. where larger quan- 

 tities were employed. A very perceptible growth of mycelium was possible in 

 practically nitrogen-free media, but in such cases the nitrogen content was 

 found by analysis to fall within the limit of error of the method. In addition 

 the mycelium showed a starved, shriveled condition, as if deficient in some 

 necessary element. In these cases mycelia having a dry weight of 3 to 6 mg. 

 gave amounts of nitrogen within the limit of error. Conversely, where the dry 

 weight of mycelium was not more than 6 to S mg., this weight could jjrobably 

 be taken as an index of little or no nitrogen fixation. 



A bibliography of the subject is appended. 



Spornlation in Aspergillus niger and A. fumigatus, B. Sauton {Compt. 

 Rend. Soc. Biol. [Pans], 74 (1913), No. 6, pp. 263-265).— Experiments were 

 made to ascertain whether certain small proportions of phosphorus or mag- 

 nesium permit even weak development of mycelium without sporulation as in 

 the case of potassium, iron, manganese, and sulphur (E. S. R., 29, p. 30). 



The author employed as nutritive medium Raulin's solution, except that 

 phosphorus and magnesium were present in very small quantities as regards 

 one or both. It was found that sporulation of both the fungi was increased by 

 decreasing the proportions of both phosphorus and magnesium. In the case, 

 however, of magnesium, as of sulphur, iron, etc., a very small proportion gave 

 no sporulation. Attempts to substitute glucinium for magnesium in Raulin's 

 fluid, suggested by the analogy presented by these metals, gave negative results 

 with both of these fungi. Phosphorus seems absolutely indispensable to both 

 fructification and growth. In very weak solutions, mycelial growth is very 

 slight, but sporulation is very rapid, distinguishing phosphorus from other 

 elements investigated in this respect. It is claimed that all constituents of 

 Raulin's liquid have been shown to participate in spore formation with the 

 possible exception of zinc. 



The water requirements of plants, L. J. Bkiggs and H. L. Shantz (V. 8. 

 Dept. Agr., Bur. Plant. Indus. Buls. 284. PP- 49, pis. 11, figs. 2; 285, pp. 96, figs. 

 6).— This consists of 2 parts. 



I. Investigations in the Great Plains in 1910 and 1911. — This bulletin gives 

 the results of pot and field investigatious carried on with a number of field 

 crops and indigenous plants to determine their water requirements under the 

 conditions occurring in the Great Plains. 



The experiments were conducted at Akron. Colo., and at Amarillo and Dal- 

 hart, Tex. By the term water requirement the authors indicate the ratio of 

 the weight of water absorbed by a plant during its growth to the weight of dry 

 matter produced. In the pot experiments large pots were used and so protected 

 that the loss of water was limited to that occurring from the transpiration of 

 the plants. 



