ShuU: Three New Mutations 



359 



ana in many details of form, but in 

 1920 in family No. 193 there occurred 

 among 78 typical Lamar ckiana plants 

 and 1 biparlita, one plant which was 

 indistinguishable from Lamarckiana in 

 nearly all details of form and size, but 

 which had the buds entirely free from 

 any trace of red pigment. The color 

 of the papillae on the stems was not 

 observed, but as all of the offspring 

 of this plant by self-fertilization, have 

 been wholly free from red papillae it 

 may be assumed with assurance that 

 this original specimen of mut. pervirens 

 was characterized not only by wholly 

 green buds, but also by wholly green 

 stems. 



SIMILARITY TO LAMARCKIANA SHOWN 

 BY PARALLEL MUTATIONS 



That mut. pervirens has essentially 

 the same genotypic constitution as 

 Lamarckiana, except in this complete 

 loss of red pigmentation, is indicated 

 by the composition of its progeny 

 (No. 2046) for not only were there 140 

 pervirens, practically indistinguishable 

 in form and habit from Lamarckiana, 

 but there were in addition to these, 

 two mut. lata, one mut. ohlonga and 

 one mut. hipartita, which differed from 

 the parallel forms found in Oe. La- 

 marckiana only in being wholly free 

 from red-pigmentation on buds and 

 stems. There were also five unidenti- 

 fied mutants, one of which closely 

 resembled scintillans, another nanella 

 and a third hipartita. 



ABSENCE OF PIGMENT AN AID TO 

 GENETIC ANALYSIS 



Since 1913 I have been tracing the 

 genetical behavior of a factor Rs 

 for intense reddening of the stems, 

 but have had difficulty in many 

 combinations because forms which do 

 not possess this factor frequently 

 show considerable reddening of the 

 stems. In these the redness of the 

 stems advances with advancing age, 

 and is especially intensified with the 

 onset of autumn coloration, so that 

 classification into red-stemmed and 

 green-stemmed series has become in- 

 creasingly difficult in some crosses,with 



WARTLIKE OUTGROWTHS, A CHARAC- 

 TERISTIC OF THE FUNIFOLIA 

 MUTANT 



The above sketch, drawn by J. Marion 

 Shull, shows a portion of a leaf of the funifolia 

 mutant bearing the pecuHar wartlike out- 

 growths which frequently occur on highly 

 developed specimens of this type. (Fig. 12.) 



the advance of the season. The great 

 advantage to be derived from the 

 discovery of a form wholly free from 

 red pigmentation, and having at the 

 same time the splendid qualities of 

 vegetative vigor and fecundity which 

 have made Oenothera Lamarckiana 

 such a satisfactory subject for genetical 

 studies, will be sufficiently obvious, 

 and it may be confidently expected that 

 with the aid of a recessive type which 

 is free from red coloration on both 

 buds and stems, and whose stems show 

 no trace of autumn reddening the 

 pigmentation factors will be capable 

 of a much sharper analysis than has 

 been possible heretofore. 



Oenothera Lamarckiana mut. vetaurea 

 mut. nov. 



THE FIRST BREAK IN FLOWER COLOR IN 

 VARIANTS OF LAMARCKIANA 



Few characters are more constant 

 throughout a large genus than is the 

 yellow flower color of the Oenotheras. 



