1909] CURRENT LITERATURE 479 
grains. In the round pea are large potato-shaped grains (p grains), while the 
wrinkled pea has compound grains (c grains), averaging six parts to a grain. 
In addition, both types possess a few very small circular grains and in the wrinkl d 
pea are found occasional f grains, though these are very rare. In the hybrid F, 
the starch grains are perfectly intermediate between those of the parents, although 
the character roundness is dominant. The majority of the grains in F, are large 
and round; some, however, are compound, averaging three parts to a grain. 
Heterozygotes (DR) in the F, were of a similar sort, but extracted wrinkled peas 
in F,; showed an occasional p grain. DARBISHIRE concludes that round differ 
from wrinkled peas in four pairs of characters: (1) the shape of the pea, (2) its 
absorptive capacity for water, (3) the shape of the starch grain, and (4) the con- 
stitution of the starch grain, i. e., whether single or compound. 
In a more recent paper the anihoe tests the theory of ancestral contributions 
as applied to Mendelian heredity. Yellow and green peas obtained from India, 
Canada, China, Russia, and other sources gave similar results. The recessive 
character appearing in F, was shown to behave as though it was as pure as that 
borne by a pure race. It was concluded that “there is nothing like ancestral 
contributions within the limits of a single unit character,” and that in such cases 
in predicting the results of a cross, ‘‘the somatic characters not only of the parents 
and of the ancestors of the individuals mated, but of the individuals themselves, 
may be left out of account,” aioe being based on the theory of the contents 
of the germ cells.—R. R. GATE 
Diversity in cotton.—Several bulletins by Cook and his associates in the 
Department of Agriculture*® are not only of great commercial value in directing 
the activities of cotton growers, but are also of considerable interest as studies 
in variability and its causes, and the results of crossing. Without attempting 
to mention all the topics considered, one or two of them may be referred to as of 
special interest. The diversity found in Egyptian cotton introduced into Ari- 
zona is = to be ts — kinds: (1) diversity due to hybridization, (2) 
diversity due t mplet tization, (3) diversity due directly to differences 
in the physical esvirenae and (4) diversity i in different parts of the same plant. 
Slight differences in the external conditions have large effects in the productivity 
of individuals by determining the production of sterile or fertile branches. 
36 Cook, O. F. Page agn es of a primitive character in cotton hybrids. Bureau 
Pl. Ind., Circ. 18. pp. 11. 190 
he s cla is line breeding over narrow breeding. Bureau PI. 
Ind., Bull. ae Pp. 45. 1909 
pressed and fauinstheed characters in cotton hybrids. Bureau PI. 
, Sup 
Ind., Bull. 147. pp. 27. 1909. 
Coo K, O. F., McLacaian, A., AND Meape, R. M., A study of diversity in 
ei cotton. Bureau PI. Ind., Bong 156. pp. 60.. pls. 6. 1909. 
Coox. O. F., Local adjustment of cotton varieties. Burean PL. Ind., Bull. 159. 
PP-75- 1909. 
