FIELD CROPS. 35 



normally present in the leaves. In the varieties which have yellow leaves or 

 which do not uormally redden and in the yellow flowers of narcissus the pig- 

 ment may be changed into a red coloring material by reduction. 



On differential mortality with respect to seed weig'h.t occurring in field 

 cultures of Pisum sativum, J. A. Harris (Aincr. Nat., j^S (1914), j\'o. 56"6', 

 pp. 83-86).— Claiming to have shown previously (E. S. R., 28, p. 636; 29, p. S29) 

 that for the dwarf varieties of Phaseolus vulgmis the mortality of apparently 

 perfect seeds (failure to germinate or to complete the life cycle) is not random, 

 the author reports on an extension of these studies to P. sativum. He states 

 that in these Legumiuosse the mortality which occurs before germination is 

 differential, but that in both cases wider series of experiments and refinement 

 of methods of analysis are necessary to establish fully the nature and imme- 

 diate (physical or chemical) cause of this selective death rate. 



Studies in seedless fruits, G. Negki {Ann. R. Accad. A(jr. Torino, 55 {1912), 

 pp. 517-581). — The author gives the results of extended investigations on the 

 subject of fruit development without seed formation, and describes apogamous, 

 parthenocarpic, and other forms of fruit in which the ovary is stimulated to 

 development without the ovules being fertilized. A bibliography is api^ended. 



Origrin of species in polymorphic genera, H. ue Vries {Rrv. G6n. ScL, 

 25 (1914), -A'o. 5, pp. 181-191). — From his observations and experiments the 

 author concludes that in as polymori^hous a group of plants as CEnothera muta- 

 tion is not a special quality of (B. lainarckiana alone, but is also a character- 

 istic of other si>ecies. It is held that mutation is a cause of the wide range of 

 forms observed in many wild species as well as in cultivated forms of many 

 plants. (E. lamnrckiana is considered as possessing a considerable number of 

 characters that are in a state of very unstable equilibrium, and to this fact 

 is due the succession of forms that have been experimentally derived therefrom. 



The vegetation in the vicinity of Leyni in relation to agriculture, E. 

 Ferrari {Ann. R. Accad. Agr. Torino, 55 {1912), pp. 459-515). — A report is 

 given of a study of the various types of plant associations with reference to 

 the possible agricultural adaptations of the soil. 



The flower-finder, G. L. Walton {Philadelphia and London, 1914, pp. 

 J XVI +394, pis. 17, figs. 573). — ^This is a popular work for the identification of 

 common wild flowers, and is designed for the novice who wishes to determine 

 some of the more common fruits and flowers. The plan is to identify the 

 flowers and fruits by their color and other marked characteristics. Charts are 

 furnished for the different colors which are commonly represented in wild 

 flowers, from which references to definite groups are given, and, except where 

 only slight differences occur, all of the species are illustrated by line drawings. 



FIELD CEOPS. 



Forage crops: Annual grasses and roots, C. G. Williams and F. A. Welton 

 (Ohio Sta. Bill. 269 {1914), PP- 165-197, figs. iS).— This bulletin gives cultural 

 notes for corn for silage, sorghums, millets, rye, wheat, oats, mangels, sugar 

 beets, turnips, and rape. 



Tables show analyses and yields per acre of 8 varieties of corn for silage for 

 5 years. The total yields ranged, from 4.86 to 20.71 tons per acre, protein from 

 463.6 to 567.6 lbs., crude fiber from 1,204.5 to 1,795.5 lbs., nitrogen-free extract 

 3,880.8 to 4,700.2 lbs., and fat from 94.5 to 144.8 lbs. per acre. 



Results of tests for thickness of planting com for the silo showed " that the 

 differences in yield of corn per acre vary widely with the season. In 1909 and 

 1912 the 4-in. drilling led by a wide margin, while in 1911 and 1913 it was a 

 little behind the 6-in., and but slightly ahead of the 10-in. In 4 of the 5 years 



