326 EXPERIMENT STATION RECORD. 



differences in size or other characters, in respect to which each race shows con- 

 tinuous variation about a different mean, the Fi progeny are of intermediate 

 size. They may or may not be more variable than the races crossed, but quite 

 commonly are not. The Fa generation as a whole commonly varies about the 

 same intermediate mean as the Fi generation, but its variability as measured 

 by the standard deviation or th<j coefficient of variation is usually greater than 

 that of the Fi generation." 



In regard to the pure line theory, the author points out the importance of 

 knowing w'hether or not this theory is true and claims there is a lack of demon- 

 strative or even probable evidence in its favor. He believes it is desirable to 

 devise ways of putting this theory to an experimental test. 



A bibliography is appended. 



Breeding experiments which show that hybridization and mutation are 

 independent phenomena, R. R. Gates (Ztschr. Induktive Abstam. u. Verer- 

 hungfiJchrc, 11 (1914), No. 4, pp. 209-279, pi. 1, figs. ^5).— Presenting and dis- 

 cussing a large body of cytological and breeding data obtained in work with 

 CEnothera, including crosses between forms differing in so many characters that 

 they are regarded as equivalent to interspecific crosses, the author claims to 

 have shown that the mutations which also appear in these crosses are not the 

 result of recombination or blending of characters in the hybrids, but that they 

 have a different cause, being independent of all laws of hybrid combination and 

 hybrid splitting. Even in forms that have been crossbred, some of the muta- 

 tions at least owe their origin to a cause which is independent of the mere 

 mingling of characters in hybrids. Mutation in CEnothera is deemed a unique 

 process, no amount of hybrid combination or splitting, Mendelian or otherwise, 

 being sufficient to account therefor. 



A bibliography is appended. 



Genetical studies on CEnothera, V, B. M. Davis (Ztschr. Induktive Abstam. 

 u. Vcrerbungslehre. 12 {1914), ^o. 3-4, pp. 169-205, figs. 22). — Descriptions and 

 illustrations are given of the results of reciprocal crossings among species of 

 CEnothera. The author states that the terms patroclinous and matroclinous are 

 here used in a relative sense, indicating strong resemblance but not perfect 

 duplication of the characters concerned, he having obser\-ed no certain in- 

 stance of the transmission of a morphological character of either species in a 

 cross to the Fi hybrids without more or less alteration. 



The character of anthocyanin coloration exhibited wide fluctuations, fre- 

 quently making it difficult to judge whether an absolute character or a blend 

 was under consideration. Patrocliny and matrocliny are, however, regarded 

 as very striking phenomena, demanding an explanation which is not yet 

 evident. 



The author concludes that there seems to be left to us only the vague concep- 

 tion of prepotency, which is really no explanation, although it serves at least 

 to name the phenomenon. There is in these hybrids a strong prepotency of the 

 male parent over the female, although this does not affect all of the characters. 

 An important feature of this prepotency lies in the fact that it is not a pe- 

 culiarity of certain individuals of the same sex, but that it is a prepotency 

 of one species over another with respect to the characters concerned. 



Kesults obtained by crossing a wild pea from Palestine with commercial 

 types, A. W. Sutton (Jour. Linn. Soc. [London], Bot., 42 {1914), No. 2S6, pp. 

 427-434, pis. 3, fig. i).— In continuation of a previous note (E. S. R.. 30. p. 330), 

 the author gives some results obtained by crossing a wild pea collected by him- 

 self in Palestine with a variety of Pisum sativum. Some of these hybrids have 

 been carried through the fourth generation, and several new types are de- 

 scribed.. 



