1916] AGRICULTURAL BOTANY. 819 



Mendelian inheritance in varietal crosses of Bryonia dioica, W. N. Jones 

 and M. C. Raynee (Jour. Genetics, 5 (1916), No. S, pp. 203-224, pis. S, figs. 6).— 

 Results of breeding experiments on the genetical behavior of certain differ- 

 entiating features in two strains or varieties of B. dioica are reported. 



The autlior states that the absence of a waxy bloom on the ripe berries of 

 one variety behaves as a simple dominant to the presence of a waxy bloom on 

 the berries of the other variety, the presence and absence of bloom behaving 

 as a pair of simple allclomorphic factors. The observed proportion of two- 

 carpellary to three-carpel lary flowers obtained by crossing the two varieties 

 can be interpreted by assuming the cooperation of two factors. The numbers 

 of vascular bundles in the stems of these two varieties are typically 10 (5+5) 

 and 14 (7+7) respectively, the capacity to increase the number of bundles 

 beyond 10 behaving as a simple dominant to absence of such capacity. Differ- 

 ences relating to habit and foliage are evidently complex in origin, requiring 

 further study. It is regarded as determined that crossing leads to the pro- 

 duction of new types in the second generation, that segregation occurs involving 

 the reappearance of the original characters of the grandparents in the Fj 

 generation, and that the number of factors for leaf shape is probably not 

 over two. 



The experiments on Bryonia emphasize the need for caution in the sub- 

 division of existing species without regard to breeding tests. It is thought 

 that a number of segregates showing morphological differences due to new 

 combinations can arise from the intercrossing of a few stable types within the 

 limits of a so-called species. The stability of these new forms can be tested 

 only by breeding, and the extreme types among them may be connected by an 

 almost continuous series of transition forms. 



Studies on size inheritance in Nicotiana, E. M. East (Oenetics, 1 (1916), 

 No. 2, pp. 164-176, figs. 4)- — The results of a study of simple and obvious Men- 

 delian phenomena, as noted in a cross between two varieties of N. longiflora, 

 are reported. 



The author states that the minimum number (not less than eight) of re- 

 quirements, mostly independent mathematically, which should be met by 

 pedigree culture data when all populations succeeding the original cross are 

 obtained by self-fertilization, are met by data here presented or elsewhere ob- 

 served, and that not one fact has been discovered to be directly opposed to them. 

 Considering these data apart from other known facts, it is held that while the 

 evidence tends to justify the use of the plural segregating factors In the inter- 

 pretation of size inheritance, dogmatic conclusions should not be drawn from a 

 single set of experiments. Numerous size studies by authors mentioned should 

 be considered together in order to arrive at a reasonable judgment as to the 

 mechanism by which such characters are transmitted. 



Some notes on the Linaceae. The cross pollination of flax, J. V. Eyre and 

 G. Smith (Jour. Genetics, 5 (1916), No. 3, pp. 189-197).— It is stated that while 

 testing many species of LinacejE for cyanophoric glucosids during the past 

 three years, it was noted that those species having white, red, or blue flowers 

 were more or less richly cyanophoric, whereas the yellow-flowered species, 

 which usually show a different habit, failed to yield hydrogen cyanid and 

 appeared to lack cyanogenetic enzym. Studies made during 1913 on a large 

 number of both blue and yellow flowered species have confirmed observations 

 previously reported (E. S. R., 28, p. 503). 



In view of an expected early interruption of this study, a provisional report 

 is made on the details of recent progress in work, which is still incomplete. 



Note on experiments with flax at the John Innes Horticultural Institution, 

 W. Bateson (Jour. Genetics, 5 (1916) , No. 3, pp. 199-201 ) .—The author reports 



