FIELD CROPS. 133 



On the sljellbark hickory three forms of ectotrophie niycorrhiza were fomul. 

 One of these is bright yellow in color, distinctly filamentous, and has numerous 

 short branches extending into the soil. The second form is brown, the fungus 

 mantle consisting of pseudoparenchyma such as is found in many lichens. The 

 third form is whitish or nearly colorless, distinctly filamentous, but smooth on 

 the outside. 



On oaks the same variations in microscopic structure were found, but with- 

 out the variations in color, all specimens collected being whitish. On larch a 

 form was found in which the outer cells of the root cortex were pushed apart 

 by the growth of mycelia between them. Endotrophic mycorrhiza were found in 

 great abundance on maples, while on American linden the same fungus was 

 found to be both ectotrophic and endotrophic. 



Contributions on the colorless sulphur bacteria, G. Hinze (Ber. Dent. Bot. 

 OeselL, 31 (1913), No. 4, pp. 189-202, pi. i).— The author studied two sulphur 

 bacteria found in slime and mud in the Bay of Naples, one being already 

 known as Monas miilleri, the other being considered as new and named Thio- 

 vulum n. gen. 



Culture of micro-organisms, E. Kuster (Kultiir der Milcroorganismcn. Leip- 

 sic and Berlin, 1913, 2. ed., rev. and enl., pp. 218, figs. 26). — This is the second 

 edition of a book previously noted (E. S. II.. HO. p. 93r5). 



FIELD CROPS. 



Causes of the increased yields of agricultural crops during the last three 

 decades, D. Leiin (IUus. Landiv. Zig., 32 {1912), Xos. 69, pp. 627, 628; 70, pp. 

 636-638). — The author discusses the increased yields during the last three 

 decades and attributes them to the increased intelligent use of commercial 

 fertilizers, the introduction of better producing varieties, management systems, 

 and methods of soil cultivation. 



Making money on farm crops, F. B. Nichols (St. Joseph, Mo., 1913, pp. 

 288, figs. 80). — This book discusses soils for crops and the improvement of farm 

 crops, with chapters on the production of alfalfa, clover, cowpeas, com, wheat* 

 oats, and the sorghums. 



[Experiments with field crops] (Abs. in- Jour. Bd. Ayr. [London}, 19 (1913), 

 Nos. 11, pp. 936-939; 12, pp. 1029-1031; 20 {1913), Xo. 1, pp. .^2-.^7).— Several 

 abstracts are given of reports of locally conducted experiments in Great Britain 

 with grasses, mangolds, wheat, barley, sugar beets, permanent pastures, potatoes, 

 oats, peas, tobacco, millet, and Chinese alfalfa. 



Field experiments {Yorkshire Council Agr. Ed. and Univ. Leeds [Pamphlet] 

 85, 1912, pp. 2-36). — In fertilizer experiments with meadow hay, the un- 

 manured plats consisted chiefly of bent and sorrel. Barnyard manure applied 

 each year seemed to encourage the growth of the better grasses, especially fox- 

 tail and cocksfoot, and to repress bent. Applied in alternate years it appar- 

 ently increased the growth of the desirable grasses, particularly golden oat 

 grass, rsing barnyard manure and complete artificials in alternate years en- 

 couraged foxtail and cocksfoot, golden oat grass, and tall oat grass, but the 

 highest percentage of good grasses followed, a complete mixture of artificials 

 applied every year. With niter and superphosphate applied annually desirable 

 grasses and also sorrel to a slight extent were fostered, while with nitrate of 

 soda alone cocksfoot and tall oat grass throve at the expense of bent, and with 

 sulphate of ammonia alone cocksfoot throve at the expense of foxtail and 

 golden oat grass. Lime did not seem to increase the yield of hay but to sup- 

 press the growth of sorrel. 



