632 EXPEEIMENT STATION RECORD. 



The author advises a study of the various types that are presented by wild 

 species which appear to have some economic value, after which seed of all 

 should be collected, planted separately to avoid the possibility of crossing, and 

 again studied. Only those that have superior merit should be introduced into 

 cultivation. In this way many worthless introductions and much waste of 

 time in testing them would be avoided. 



The inheritance of sizes and shapes in plants, R. A. Emerson (Amer. Nat., 

 JiJf (1910), No. 528, pp. 739-746). — A preliminary account is given of studies on 

 the inheritance of size and shape of fruits of gourds and summer squashes, size 

 and shape of bean seeds, and size of grains and height of stalks in maize. 

 There appears to be a blending of these characters in the Fi generation, fol- 

 lowed by a segregation in the F2. These phenomena, the author states, are 

 more complex than those of the inheritance of color, etc. 



The author calls attention to some of the possible causes of error in interpret- 

 ing results of this kind. 



The nature of graft hybrids, D. H. Campbell (Amer. Nat., Jf5 (1911), No. 

 529, pp. 41-53, flg. 1). — The author gives a description of the graft hybrids of 

 Solanums produced by Winkler (E. S. R., 21, p. 320). The different hybrids 

 were studied, but of these only S. darwinianum appears to be a hybrid in the 

 strict sense of the word. 



All of the hybrids were propagated by cuttings and, with the single exception 

 of 8. koelretiterianmn, produced ripe fruit which in every case was more or less 

 intermediate in character between the fruit of the nightshade and the tomato. 

 In a number of instances spontaneous reversions were observed, and in the 

 second generation all the seedlings derived from the hybrids reverted to the 

 parent form which the hybrid most nearly resembled. 



The study of the tissues of S. darwinianum indicated that the subepidermal 

 tissue from which the sporogenous cells develop is of genuine hybrid nature, 

 arising from a fusion of the cells, including the nuclei derived from the two 

 parent forms. 



The inheritance of color and other characters in tlie potato, R. N. Salaman 

 (Jour. Genetics, 1 (1910), No. 1, pp. 7--'i6, pJs. 29, figs. 2). — The experiments 

 reported were begun in the spring of 1906 and are still in progress, the author 

 giving an account of some of his observations on the inheritance of different 

 characters. 



He has found among the domestic varieties that the twist of the leaf is a 

 recessive character, while length of tuber and depth of eye are dominant to 

 roundness and shallowness. Purple is dominant to red in the tubers, and red 

 to white. 



Studies made with some of the wild species of Solanum indicate that Sf. 

 etuherosmn is not subject to the same laws of dominance as the domestic 

 varieties of potatoes. Among the seedlings of this species are some which 

 thus far are immune to attacks of Pliytoplitlwra infcstans, and this immunity 

 on the part of S. ctitherosum has proved to be a recessive character. 



The author concludes that S. etuberosum may be a hybrid, and, if so, that 

 its parents are possibly native species. 



The mode of inheritance of stature and of time of flowering in peas, 

 F. Keeble and Miss C. Pellew (Jour. Genetics, 1 (1910) No. 1, pp. 47-56). — 

 The experiments of the authors throw some light on the factors which deter- 

 mine height of peas and the mode of inheritance of earliness and lateness of 

 flowering in this species. It was found that the flowering period was defi- 

 nitely associated with the length of internodes and thickness of the stems. Tall- 

 ness was correlated with the same factors, and early flowering was associated 



