258 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



wide ; stem 8-12 inches high ; perianth : sepals 2 inches long, pale- 

 yellow, spotted with purple; petals erect, 1 inch long, pale yellow; 

 style arms, deeper yellow. — G. H. 



Irises, RegreliO-Cyclus. By F. Demo {Rev. Hort. September 16, 

 pp. 428-9; colom^d plate). — The plate represents two very charmingly 

 tinted forms — 'Artemis,' pm^ple lilac, veined with deep purple, with 

 plum-coloured patches, a cross between I. Korolkowii concolor, perhaps 

 the least vigorous of the Eegelia section, and I. Mariae, the least 

 floriferous of the Oncocyclus, and yet the offspring is very vigorous, 

 and twenty-two flowers have been counted on one plant; 'Isis,' 

 1. Korolkowii x /. Susia7ia, is a rosy violet, purple veined, with outer 

 segments mahogany colour, veined with deep brown. Other fine 

 hybrid varieties are described. — G. T. D. 



Irrig'ation in Idaho. By James Stephenson {U.S.A. Dep. Agr., 

 Off. Exp. Stn. Bull. 216; September 1909; map). — There is an area 

 of 65,000 square miles in Idaho in which agriculture cannot be carried 

 on without irrigation, and this bulletin contains an account of the 

 various efforts that are being made to provide this irrigation by private 

 enterprise, by water companies under the provisions of irrigation laws, 

 by Government, and by local public bodies. These efforts are still in 

 their infancy, however, and the State irrigation laws themselves are 

 still incomplete as far as regards some of the more thorny questions of 

 private water rights on all the streams and sources of supply and of the 

 relative rights between the citizens of different States claiming water 

 from inter-State streams. — M. L. H. 



Irrig'ation Investigations. By J. A. Widtsoe {U.S.A. Exp. 

 Stn., Utah, Bull. 105; August 1909; plates). — An account of a series 

 of experiments undertaken at Utah for the purpose of determining the 

 conditions under which a maximum amount of vegetable substance of 

 best quality may be produced with a minimum amount of water. The 

 methods employed were to grow plants in pots filled with known weights 

 of differently composed soils and to which definite amounts of water 

 were applied. Four different varieties of soil were used, the water was 

 applied in varying amounts, and the soil was previously treated in 

 various ways. Tables of the results of each experiment are given and 

 a summary of the whole shows that : 



1. Cultivation or hoeing largely reduced the evaporation of water 

 from bare soils. 



2. Cultivation increased generally the yield of dry matter. 



3. Cultivation is much more effective on clay and sand soils than 

 on ordinary loam. 



4. Cultivation diminished largely the amount of water transpired 

 for one pound of dry matter. 



5. Shading diminished greatly the evaporation from bare soils. 



6. More water evaporated from bare soils under surface irrigation 

 than under sub-irrigation or when the water stands near the surface. 



