824 EXPERIMENT STATION RECORD. [Vol.38 



The thickenings of the cortex cells of the submerged absorptive root? are 

 claimed to be really artefacts due to a slight shrinkage of the walls of the 

 delicate transfusion cells. The pollen shedding device is explained. The 

 endosperm is considered as a placental organ rather than as reserve material. 

 The high mortality in specially concentrated media is due in H-S mud cultures 

 to increased hydrogen ion concentrations, and in hyperconcentrated sea water 

 to the difficultj of absorption and retarded metabolism. In moist soil cultures 

 the transpiration rate is delicately balanced by available soil moisture. No 

 definite inverse proportion was maintained between tannin and dextrose during 

 the growth of the seedling. Tannase tests seemed to show that tannin does not 

 serve as reserve food in the hypocotyl. Red mangrove is facultative as regards 

 its growth in fresh or salt water, though it requires the latter for its optimum 

 development. 



A cyanog'enic Mucor, H. Guyot (Bui. Soc. Bot. Geneve, 2. ser., 9 {1911), No. 

 1-3, pp. 30-35). — A further account is given of the fungus previously reported 

 (E. S. R., 36, p. 734), which is now technically described as a new physiological 

 species, M. cynnogenes. 



A comparison of certain Bocky Mountain grasslands with the prairie of 

 Illinois, G. D. Fuller {Trans. 111. Acad. Set., 8 {1915), pp. 121-130).— The 

 author makes some comparisons between Rocky RTountain grasslands and the 

 prairies of Illinois. He states that these regions agree as regards conditions of 

 rainfall and humidity and as regards summer deficiency in soil moisture, both 

 showing a well-marked hydrarch succession passing from the aquatics through 

 the sedge moor in a closely comparable series of associations, and both possess- 

 ing a climax prairie meadow association in which herbaceous species other than 

 grasses are fairly abundant. The two regions differ in altitude, temperature, 

 length of growing season, and soil. The mountain region shows fewer aquatic 

 species and a xerarch succession comparable to nothing noted in Illinois. 



A study of the vegetation of southeastern Washington and adjacent Idaho, 

 J. E. AVeaver {Univ. [Nebr.] Studies, 11 {1917), No. 1, pp. II4, p/s. 19, flo-'<. 17}.— 

 This is an account of ecological observations made during 1912 to 1914 on the 

 three principal plant formations and subdivisions thereof occurring in this 

 region. 



The vegetation of Parag'uay, R. Chodat and W. Vischer {Bui. Soc. Bot. 

 Geneve, 2. ser., 9 {1917), Nos. 1-3, pp. 55-107, figs. 46; 4-6, pp. 165-244, figs. 

 60). — Some results are detailed of the work of a Swiss expedition for botanical 

 study in Paraguay, this account being confined to the IMalpighiacese, the 

 Podostemacese, and the Bignoniacese. 



FIELD CROPS. 



Cropping systems for the moister portion of eastern Washing'ton and 

 Oregon and northern Idaho, L. W. Fluharty (f7. S. Dept. Agr. Bui. 625 {1918), 

 pp. 12.) — Three and four year crop rotation systems are outlined in which clover 

 is substituted for the common summer-fallow method of growing cereals in the 

 region adjacent to the Bitter Root and Blue Mountains in Washington, Oregon, 

 and Idaho. This region has an annual rainfall of 20 in. or more, and comprises 

 an area of approximately 1,875,000 acres of improved farm land. A farm survey 

 made in 1915 on 246 farms in a representative portion of the district showed 

 that 30.2 per cent of the rotation area was idle each season as summer fallow, 

 while observations on a few farms where clover was employed in the rotation 

 as a substitute for sununer fallow showed an increase per acre in crop yields 

 following this practice of from 15 to 25 per cent. 



