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THE JOURNAL OF BOTANY 



and A. latifolia. Continental botanists* usually regard it as a 

 hybrid of A. arvensis and A. f equina {=A. co&rulea). However, 

 the researches of Professor Weiss point to its not being a hybrid 

 at all. Professor "Weiss artificially crossed the scarlet and the 

 blue Pimpernels ; and the resulting hybrids {f^) were plants not 

 with flesh-coloured but with scarlet corollas. Only in one or two 

 hybrids out of several hundreds was a small blue streak notice- 

 able on the otherwise scarlet petals to indicate the hybrid origin. 

 Pi'ofessor Weiss then artificially self-pollinated the hybrid Pimper- 

 nels; and in the second {f^) hybrid generation only plants occurred 

 with either scarlet or blue flowers : no intermediate colours were 

 noticeable. This applied to all the offspring obtained by reciprocal 

 crossings of the parent plants. Up to the present, the numbers in 

 the/2 generation obtained by Professor Weiss are : in descendants of 

 A.femina (female) and A. arvensis (male), sixty-two scarlet and eight 

 blue; and in descendants of A. arvensis (female) and A. femina 

 (male), twenty-five scarlet and two blue. Tlius the blue is recessive 

 and the scarlet dominant. It is proved therefore that Continental 

 botanists are in error in referring A. carnea to the hybrid of 

 A. arvensis and A. femina {= A. cmrulea). It is, of course, open to 

 Mr. Williams to argue that the blue Pimpernel used by Professor 

 Weiss was A. femina and not A. latifolia, and that it is therefore 

 possible that his own view of the origin of A. carnea may be 

 correct. This, however, is not likely to be the case, for not only 

 has Professor Weiss proved the blue colour to be recessive in the 

 offspring of A. arvensis and A. femina, but he has proved the same 

 rule to hold in other Pimpernels. For example, a pink Pimpernel 

 (for which I know no binomial) was crossed with a blue one ; and 

 here again the blue colour proved to be recessive in the f^ genera- 

 tion. Further, Mr. R. P. Gregory has proved blue to be recessive 

 in the alhed genus Primula; and work by Miss Wheldale suggests 

 that colour factors of tliis nature are far more than specific in 

 their significance. Hence, the conclusion is strongly indicated 

 that British botanists have all along been correct in refusing to 

 regard A. carnea as a hybrid. 



Professor Weiss points out that Gaertner {Bastarclenerzeu- 

 gung, 1849) states that the scarlet and blue Pimpernels do not 

 produce fertile seed when crossed ; and Professor Weiss in- 

 forms me {in litt.) that, although he has pollinated many blue 

 Pimpernels (with gland-fringed petals) from the Riviera with 

 tlie British scarlet form, he has not yet succeeded in hybridizing 

 them. 



Mendelian workers have proved over and over again tliat many- 

 hybrid products are not intermediate in character between their 

 known parents ; and Professor Weiss's hybrid Pimpernels add one 



* See, for example. Pax & Knuth in Engler's Das Pflanzenreicli, iv. 237, 

 Primulacece, pp. 322-5 (1905), where A. arvensis L. is subdivided into var. apha:- 

 nicia (Scop.) Gren. & Godr,,var. ^ canilea (Schreb.) Gren.&Godr. [ = A.femina 

 Mill. Gard. Diet. ed. 8, n. 2 (1768)], var. phmnicia x cmnilea = A. carnea 

 Schrank, and var. 7 latifolia (L.) Lange. 



