270 Non-Isolablc Races. 



multiformity and instal^ility corroborate this view. It 

 is only the commonness of variegated sorts and the great 

 interest which attaches to them which l)rings them to be 

 regarded as analogous to the best constant varieties. 

 Moreover this ^•iew is supported by tlie general opinion 

 that a complete development of the yellow color would 

 characterise the supposed constant variety, but that it 

 would at the same time of necessity lead to the destruc- 

 tion of the ])lants. In this conception variegation is re- 

 garded as an incomplete anomaly whose complete con- 

 dition would im'olve its own destruction : Imt this view 

 is incorrect.-^ Complete yellow varieties are not only pos- 

 sil)le and capa1)le of existence but actually well known in 

 horticulture, although the numl)er of such forms is small. 

 Instances can be found in seedsmen's catalogues; e. g., 

 Sambucus nigra aiirca and Fraxmiis excelsior aiirea, also 

 the aurea varieties of Chrysantheniuiu carinatuin, Mira- 

 hilis Jalapa, Scabiosa atropurpnrea, Humiilus japoniciis 

 (hifesceiis) etc. These plants, so far as I know, are all 

 either yellowish-green or golden-yellow.- They also ap- 

 pear to be very constant and never or very seldom to 

 revert to the green type. I have made a number of ex- 

 perimental sowings on a large scale of the seeds of the 

 ordinary golden-yellow variety of Clirysanfheiiiiiui Par- 

 theuiunv' (Matricaria exiuiia nana coiiipacta foliis aureis 

 Horf.) and did not find amongst the many hundred ex- 

 amples a single atavist : neither green nor variegated seed- 

 lings occurred. But amongst other commercial seeds I 

 have not found so great a degree of purity, the admixture 



^ See § 3 of this part (pp. 18-26). 



"T have not grown all the above forms myself; and it should be 

 noticed that the name aureus does not always relate to uniformly 

 colored sorts, e. g., Agave stn'aia aurea. 



^ViLMORiN, BJumeng'drtuerei, Vol. TT. p. 509. 



