Varietäten, Descendenz, Hybriden. 117 



other data it appears probable that purple and red are separate 

 Mendelian dominant characters,and that purple is epistatic to red. 

 Potato shape, round or elongated, is not so easily analised. Deep- 

 eye is considered probably recessive to shallow-eye in the tubers. 

 As a cause for the running out of asexually propagated varieties, 

 it is suggested that by continued bud propagation there may be a 

 gradual loss of the Stimulus resulting from the original cross. 



Gates. 



East, E. M., A Mendelian Interpretation of Variation 

 that is apparently continuous. (Amer. Nat. XLIV. p. 65 — 82. 

 1910.) 

 The author cites results of Nilson-Ehle showing that, e.g., 

 in wheat there are "three indistinguishable but independent red 

 characters, each allelomorphic to its absence", and in varieties 

 of oats "in one case no less than four independent characters for 

 presence of ligule, each being dominant to its absence". He then 

 describes experiments which were independently interpreted in a 

 similar manner, as indicating, e.g., the presence in some cases in 

 the endosperm of maize, of "two indistinguishable, independent 

 yellow colors". This is indicated by the fact that, when crossed 

 with white varieties, such yellow varieties give a dih5^brid ratio 

 instead of the simple monohybrid ratio. When the factors for the 

 yellow are both present together the shade of yellow is darker. It 

 thus appears that several allelomorphic pairs, each producing the 

 same character, may be independently inherited in the same indi- 

 vidual. The unanalised result of such a condition will be an 

 appearance of fluctuating variability. East suggests that, where 

 there are thus several representatives of the same character, they 

 have probably appeared through Variation in different individuals 

 and afterwards been combined b}' crossings. Where there is no 

 dominance and open poUination the curve of variabilit}^ may be the 

 same as the fluctuation curve and yet the graduations be heritable. 

 This might also explain cases of atavism, two individuals appa- 

 rently both pure when crossed giving a (rare) pure recessive. 



Gates. 



East,E.M., The transmission of variations in the Potato 

 in asexual reproduction. (Conn. Agr. Expt. Sta. Rept. p. 

 119—160. pl. 5. 1910.) 



This paper shows the similarity between the inheritance of 

 fluctuations in asexual reproduction in multicelled organisms, and 

 that in the pure lines of Johansen and Jennings. It is found 

 that neither the relative content of dr}'^ matter nor that of the 

 nitrogenous matters of the tuber can be changed bj^ selection of 

 fluctuations and their subsequent asexual multiplication. The same 

 is true of fluctuations in ^nelding power, with rare and uncertain 

 exceptions which may, however, be due to mutative changes. The 

 writer believes' that practically all cases of bud Variation are due 

 to the loss of a dominant or an epistatic character. In five varieties 

 with pink tubers white variations occured and remained constant. 

 In four other varieties changes in shape of tuber, from long to 

 round, occurred, and in two of these the change was permanent. 

 In four other cases changes from shallow to deep eyes appeared 

 and were permanent, and a peculiar Variation in the method of 



