122 GENETICS [Box. Absts., Vol. Vll, 



834. Wilson, E. H. The romance of our trees. X. The Lombardy poplar and the Babylon 

 willow. Garden Mag. 31: 317-320. 5 fig. 1920.— See Bot. Absts. 6, Entry 1473. 



835. Wilson, E. H. The cedars of Lebanon. Garden Mag. 30: 178-183. ^ fig. 1919.— 

 See Bot. Absts. 6, Entry 1876. 



836. Wilson, E. H. The romance of our trees. II, The Ginko. Garden Mag. 30: 144-148. 

 7 fig. 1919.— See Bot. Absts. 6, Entry 1877. 



837. WiMBUSH, A. Artificial regeneration of teak by sowing. Indian Forester 46: 488- 

 492. PI. 21. 1920. — Experience gained in the past work shows that early felling of the cover 

 crop is necessary to allow time for drying before burning, that seed should be carefully selected 

 and a nursery established on the ground, and that the grass should be cut before seeding takes 

 place. — E. N. Munns. 



838. ZoN, R. Effect of forests upon streamfiow. [Rev. of: Engler, Arnold. Unter- 

 suchungen iiber den Einfluss des Waldes auf den Stand der Gewasser. Mitteil. Schweiz. 

 Zentralanst. Forst. Versuchsw. Zurich, 1919.] Jour. Forestry 18:625-633. 1920.— Twenty- 

 years' record of the Emmental Experiment Station in Switzerland and ten-years' of the 

 Wagon Wheel Gap Station in Colorado have been completed, and so far the results are 

 directly comparable. In Switzerland it has been found that the annual run-off from the for- 

 ested and non-forested areas is approximately the same, the chief difference in the disappear- 

 ance of water being due to evaporation from the surface and the transpiration from the cover. 

 Forest cover has a beneficial effect upon the regime of streams; and landslides, which occur 

 more or less regularly on open lands, rarely occur in forested basins. Forests, it is shown, 

 have a beneficial effect on the discharge and the amount of material in the water, and that 

 floods are less pronounced, though previous climatic conditions have a marked effect upon 

 the run-off and absorption in the soil. The chief effect of the forest appears to be upon the 

 permeability of the soil and consequently upon water absorption. The moisture content of 

 the soil is higher than in the open because of ground water, drouth in the open depleting this 

 reservoir, which is maintained by the forest cover. — E. N. Munns. 



GENETICS 



G. H. Shull, Editor 

 J. P. Kelly, Assistant Editor 



839. Akerman, a. Jakttagelser rorande strafusarios pa varvete sommaren 1917. [Observa- 

 tions on a Fusarium disease of spring wheat.] Sver. Utsadesforen. Tidskr. 28: 82-89. 1918. 



840. Allen, E. J., and E. W. Sexton. Eye-colour in Gammarus. Jour. Genetics 9: 347- 

 366. 1 pL, 1 diagram. Mar., 1920. — In Gammarus chevreuxi the eye is normally reniform and 

 pigmented black. In the second laboratory generation a red-eyed mutant appeared, Red- 

 eye is a simple Mendelian recessive to black, the F2 ratio being 3:1. In a second mutation, 

 called albino eye, the eye not only lacks pigment but is "imperfect;" it is small and variable 

 in size and shape, and has few ommatidia, which are irregularly distributed, and has unevenly 

 distributed white pigment (distribution regular in normal eye). Albino eye is a simple 

 recessive to color. Albino-eyed specimens all carry a factor for color — some for black, some 

 for red, some for both. The white eye pigment in both colored and albino eyes is quite vari- 

 able in amount. Absence of this white pigment occurs both in pigmented- and albino-eyed 

 stock. "No-white" is a simple recessive to pigment. This is a not uncommon mutation 

 appearing in some families of all the author's stocks and was seen in another species of wild 

 Gammarus. This mutation begins in at least two different ways: (a) it may appear suddenly 

 either with one eye or with both eyes affected, or (b) it may develop gradually; e.g., parents 

 with thin reticulation giving some young with thin reticulation, and some "no-white." "In 

 the albino-eyed stocks the white extra-retinal pigment shows a tendency to break up, and 



