066 EXPEEIMENT STATION RECORD. 



inent it is considered valuable to iirotect soils against erosion, and its reproduction 

 and o-rowth as coppice is ra])id and the second growth wood which matures in from 

 10 to 20 years is said to be better than the original growth. In addition to its tindjer 

 value, the beans which are produced in great abundance have a distinct value both 

 as food and feeding stuff. The bark also contains a high percentage of tannin which 

 is locally used, and a gum which is capable of making tine mucilage exudes from the 

 branches. The distribution of the mesquite is indicated and its related species, 

 the screw bean (P. 2^ubescens), is also briefly mentioned. 



Difficulties and errors in stem analysis, A. S. Williams {Forestry Quart, 1 

 [190J), No. 1, pp. 12-17). — A number of the difficulties which are met with in 

 attempting stem analysis, and the sources of a number of errors are pointed out. 



DISEASES OF PLANTS. 



Spore resistance of loose smut of wheat to formalin and hot water, W. 



Stuart {Proc. Indiana Acad. Set. 1901, pp. 275-282). — On account of the apparent 

 difference in the resistance of the spores of loose snuit to various media, a series of 

 experiments was undertaken in which spores from smutted heads were subjected to 

 various germination tests. Before being placed to germinate, they were treated with 

 varying strengths of formalin and different temperatures of hot water for varying 

 periods of time. As a result of the experiments it was concluded that the smut 

 spores themselves are easily destroyed by either formalin or hot water treatments, 

 but owing to the somewhat impervious nature of the seed coats of wheat the spores 

 frequently find lodgment in the interstices and it is difficult to reach and kill them 

 in the ordinary methods of treatment. To render the seed coats of wheat susceptible 

 to such agencies as are commonly employed for the prevention of smut, it is recom- 

 mended that the seed should be soaked for several hours in cold water prior to the 

 treatment. When so treated, a short immersion in an 0.18 per cent solution of 

 formalin or 10 minutes in water at 120° did not materially influence the germination 

 of the wheat and destroyed the smut. 



Experiments in the prevention of smut in oats, T. Johnson [Jour. Ikjit. Agr. 

 and Tech. Tnstr. Ireland, 2 {1902), No. 3, pp. 426-436, figs. ;^).— An account is given 

 of experiments conducted for the prevention of oat smut ( Ustilago avenie) in which 

 the relative efficiency of potassium sulphid, copper sulphate, formalin, hot water, 

 and the "sar" or sodium sulphid solution, previously described (E. S. R., 10, p. 154), 

 were tested. As a result of the experiments it is shown that smut of oats, which is 

 very prevalent in the west of Ireland, can be almost entirely prevented by treatment 

 of the seed, and when the cost of application and efficiency is considered the "sar" 

 or sodium sulphid solution is preferred. 



The specialization of Erysiphe graminis, E. Marchal {I'lng. Agr. Gemhloux, 

 13 {1902), No. l,pp. 10-13). — An account is given of a series of experiments con- 

 ducted with Erysiphe graminis to determine the possibility of cross inoculations of 

 this fungus from one host to another. There are said to be about 55 species of 

 grasses affected by this fungus, and the experiments briefly outlined were conducted 

 from March to June, 1902. Plants of wheat, barley, rye, and oats were cross inocu- 

 lated with the Erysiphe from different hosts. In about 15 days an abundant 

 development took place but only in those cultures where the spores had been taken 

 from host plants of the same species. A series of experiments was then undertaken 

 in which the attempt was made to transfer the mildew from various wild grasses to 

 the cultivated cereals. As a result of all his experiments, the author is led to con- 

 clude that there are a number of well defined forms of Erysiphe graminis which are 

 specialized to their res])ective hosts. Morphological Ij^ no differences can be detected, 

 but infection expei'iments invariably failed when the species of host plants were not 

 rather closely related. 



