lOlS] AGKICULTUBAL BOTANY. 331 



of the day, the species would be able to perpetuate itself in this locality by 

 nipans of seed. 



Modifications produced by sea winds in the male inflorescences of pine, 

 J. DuFRENOY (Compt. Rend. Soc. Biol. [Paris], 80 {1917), No. 4, pp. 17^, 175).— 

 The author notes the occurence, in pines exposed to sea winds, of a curving of 

 the male inflorescence with other alterations which are detailed, also of other 

 modifications apparently supporting the view that ecological conditions may 

 cause the develo]inient of rudimentary branches into structures which may be 

 reproductive, assinillative, or multiplicative in their functions. 



The bacteriological study of natural coagulation in latex of Hevea brasjli- 

 ensis, Dendlr and G. Vernet {Compt. Rend. Acad. >Sci. [Paris], 165 {1917), No. 

 3, pp. 123-126). — Hevea latex, which has when first collected a milk-white color 

 and corpuscles showing the Brownian motion, is at that time almost free from 

 bacteria. These, however, soon develop abundantly. The author noted the 

 presence of organisms, both aerobic and anaerobic, in latex. One is described 

 in some detail as to its characters and influence on coagulation, which it is said 

 to accomplish in 24 hours. Suggestions are given regarding conditions favorable 

 to the coagulation of latex. 



Sexuality in Myxomycetes, F. X. Skxipienski {Compt. Rend. Acad. Sei, 

 [Paris], 165 {1917), No. S, pp. 1 18-121). —The author describes observations 

 claimed to show that a marked sexuality exists in Didi/mium nigripes. 



Parthenogenesis in higher plants, A. C. Hagedoorn-La Brand and A. L. 

 Hagedoorn {Teysmannia, 27 {1917), No. 11-12, pp. 6^3-656, pi. 1). — An account 

 is given of the crossing of cucurbits said to iiava been produced from seed 

 without pollination with those from hybrid plants. The results, though vitiated 

 in some degree by failure ascribed to external causes, suggest some noted by 

 Honing (E. S. R., 32, p. 520; 33. p. 644). It is recommended that in cases 

 where exceptional results are obtained in the progeny of hybrids, investigations 

 be carried out to determine how far partial parthenogenesis or partial apogamy 

 in the ancestors may be responsible for the anomaly. 



Quadruple hybrids in the Fi generation from CEnothera nutans and CE. 

 pycnocarpa, with the F2 generations, and back crosses and intrcrosses, G. F. 

 Atkinson {Genetics, 2 {1917). No. 3, pp. 213-260, figs. 16). — In continuance of 

 a partial report previously made (E. S. R., 30, p. 730) regarding studies on the 

 results of crosses made with CE. nutans and subsequent studies on crossings 

 of the descendants of these hybrids, the author states that in the Fi generation 

 of the cross GE. nutansXCE. pycnocarpa four hybrid types appeared which have 

 been named, respectively, CE". hybrida niiteUa, GE. hybrida pycnella, (E. hybrida 

 tortvosa, and CE. hybrida tortuella. In the Fi generation of the reciprocal 

 cross three hybrids have been obtained which appear to be identical with the 

 first three above named, and it is thought that the fourth might appear if the 

 crossings were sufficiently numerous. 



CE. hybrida nutella is a blend hybrid. CE. hybrida pycnella and CE. hybrida 

 tortvosa are selective hybrids and are physiological homozygotes, being fixed in 

 the Fi generation and, when selfed, repeating in the F2 and succeeding gen- 

 erations. They are regarded as examples of permanent or stable dominance 

 of factors. CE. hybrida tortuella, also a selective hybrid, is not fixed in the Fi. 

 When selfed it dissolves in the F2 into numerous types, some of which are 

 considered as showing that certain factors are activated in this generation 

 which wei'e subordinate in Pi. 



The production of four hybrid types in the Fi is considered as an example 

 of multiple dominance. In back crosses there appear five cases of patrocliny 

 with ten cases of splitting into two types and four of splitting into three types. 

 In the intercrosses there are two cases of patrocliny, three of splitting into two. 



