W. F. R. Wkldon 47 



clearly uiulerstciod. I tlu-reforo proposc, as opportuiiity offers, to describi^ the 

 variability of such races as I caii obtain, ainong thosc which are said to obey 

 Mendels laws, and to consider how far the Statements niade concerning them are 

 affected by the euiployment of Mendel's very imperfect system of units. 



II. Lychnis diurna and Lijchnis vespertina. 



In the Report by Mr Bateson and Miss Saiindors the results of crossing normal 

 L. vespertina and L. diurna with white and red-flovvered glabrous varieties are 

 described ; it is said that the phenomena " follow Mendel's law with considerable 

 aecuracy, and no exceptions that do not appear to be merely fortuitous were dis- 

 covered" {I.e. p. 15). Apart ft'om the great uncertainty involved in the use of 

 " hairy " as a definite category alternative to " glabrous " (which will be dealt with 

 later) these experiments are of interest, because a parallel series of crossings had 

 already been carried out by Professor de Vries, who nsed the same glabrous 

 varieties as those used, at least in some cases, by our authors. They express theni- 

 selves as " specially indebted to Professor de Vries" for them; and they add in a 

 footnote, " The discovery by de Vries of a wild specimen of L. vespertina var. 

 " glabra, and the artiticial production from it of a smooth red-flowered form are 



"described in his 'Erfelijke Monstrositeiten,' p. 10 " Now I have not been able 



to find a work by Professor de Vries, under this title, which contains a page 10 ; 

 but in the Botanisch Juarboek, Jaargang IX. 1897, pp. 62 — 93, there is a paper 

 by him entitled "Erfelijke Monstrositeiten in den ruishandel der botanischen 

 tuinen." Under the heading Lychnis vespertina glahra I find the following State- 

 ment (p. 71): "In August 1888 I coUected seed of Lychnis vespertina in a wood 

 "neai- Hilversum. Among the plants produced in niy experimental garden in 

 " the following year were some completely glabrous exaniples. I isolated these, 

 " and in the course of some generations the glabrous race has been rendered 

 "stable (geheel standvastig) as a result of coiitinued selection (door voortdurende 

 " selectie). It seems never, or only very rarely, to pi'oduce atavistic individuals. 



" Traces of hairs are still to be found here and there, especially upon the young 

 " plants. This point is worth closer investigation." 



This race of "glabrous" plants was therefore established by a process of 

 selection, and seven or eight years after it was first observed it still produced traces 

 of hairs. There is no evidence in the account given to show whether the .seed 

 came originally from a glabrous wild plant, as suggested by Mr Bateson and Miss 

 iSaunders, or not; but they may have fuller information from Professor de Vries. 

 In auy case the first glabrous plants observed did not behave as " mutatious," but 

 as we should expect extreme variations from the hairy type to behave ; so that 

 several generations of selection were required in order to fix a stable race with 

 their characters. Although its establishment by continued selection suggests that 

 this glabrous race had not at first the properties of a " recessive " race in Mendel's 



