STUDIES OX THE GENETICS OF FLOWER-COLOURS, ETC. 119 



lu each of these crosses their i^j-offepriiig are composed appi-oxiiuately of 3 

 domiuauts and 1 recessive, aud the fact that iu each of the aljove (3) we 

 have a mouohybiid instead of a chhybrid segi-egatiou is explained by the 

 assumption tliat iu AquHecjia A. aud Ji, and in tlie Rabbit C aud H are iu 

 absolute liukage. This explanation, though yet hypothetical, seems to me not 

 improbable iu -view of ni}' results in the a'oss mageuta x orange just mentioued, 

 because iu the latter case the absolute linkage exactly similar to that assumed 

 iu Aquilcgia und the Jiiibbit has been, not merely aS3U!ui3d, but adequately 

 proven. 



Morgan aud his school are iucUned to explain the case of Aqv.ilcfjia aud 

 the liabbit above given by means of their theory of multiple allelomoiiihisua.' 

 I will uot enter here into the discussion which of the two alternative Inpjtheses 

 will better explain the above cases, but I will simply state that what I have 

 observed in i"espect to the cross iu Porhdaca coiTespouds exactly to ^luit the 

 hypothesis advanced by Bauk and Puxnett demands. 



Note on the so-called " pseudo-white " Race. 



Fseudo-iuMte is the name gi-\cu to a peculiar race of white colour which 

 has newly ai'isen in my culture. In this race leaves aud stems are reddish 

 as in coloivred varieties, but the corolla is white, though slightly flashed with 

 magenta, es^jecially in its periphery, aud each petal is generally furuished with a 

 mageuta spot at its basal part (" Herzfleck " of Germau authors); fiLaments, 

 styles and stigmas are reddish (PI. 11, %. 6). This race may belong either 

 to that type in wliich the production of anthocj'auiu is inhibited, or t<j that 

 which Miss Wheldale calls " partial albiuo."- One pseudo-white was pnxhiced 

 in the i^j-oifepring ex white-II x mageuta (s. the Table Y), iu all probability 

 by mutation, but it may Ije produced regular^ iu the oflspriug of certain 

 crosses of white-IH, aud very probably according to Mendelian rule : thus, for 

 instance, the cross orange x white-Ill lias been followed up till F., aud this 

 fact has l)een made probable, though the details of the results obtained by me 

 will uot now lie published, because ihej are yet far fiom complete. Below I 



' The Medainuim of ^feiulelinn IkredUy. Kew-York, l:)lö, i)p. 157 ; also, Sttetevant, Amer. 

 Katurallst, Vol. 47, 1913. pp. 234-238. 



2 The Ardhoq/anin Pigments of Plants, Cambriilge 1916, p. 1.Ö3. 



