THREE NEW MUTATIONS IN 



OENOTHERA LAMARCKIANA 



Interesting plant forms found in a strain of evening primross obtained from 



Professor De Vries. These mutants, showing new variations in leaf 



structure, pigmentation of stalk and buds, and color of flowers 



afford further material for analysis of this important group. 



(iliORC.li H. SlIULL 



Princeton University, Princeton, New Jersey 



AW one engaged extensively in 

 breeding Oenotheras discovers 

 many new as well as old mutant 

 types. The less striking of these are 

 identified with difftcully and it does not 

 seem desirable lo encumber the litera- 

 ture with distinctive names for them. 

 Now and again, however, a form ap- 

 pears w^hich has such definiteness that 

 it may be profitably used in breeding 

 exi)eriments, and references to these 

 are facilitated by assigning to them 

 names in harmony with the names 

 already iniblished for the other mutant 

 types. 



Among the mutations which have 

 appeared in my cultures there are sev- 

 eral which have exceptional interest and 

 these are being used in numerous 

 breeding experiments. Since they are 

 destined to enter to a greater or less 

 extent into the future literature of the 

 group and since they have a certain 

 amount of interest in themseKes, quite 

 independently of the experiments in 

 which they are being employed, it 

 seems desirable to give them a publicity 

 which will serve to validate the names 

 which are being used in the notes on 

 tlieir genetical behaxior. 



Since 1905 1 Ikuc l)een ki-eping, in 

 addition to main- other Oenotlu-ra cul- 

 tures, a strain of cross-bred Oenothera 

 Lamarckiana which originated from 

 nine original rosettes colk-cted for nu- 

 by I'rofessor de Vries in tlie same field 

 at Hilversum, Holland, from which he 

 had secured the material for the initia- 

 tion of his own Oenothera cultures 

 about twenty years before. These cid- 

 tures ha\e been maintaiiu-d, year after 

 year, by crossings so arranged that 



every^ progeny in the strain has had four 

 distinct grandparents. The three mu- 

 tations here described ha\e all arisen in 

 this cross-bred strain. 



Oenothera Lamarckiana mut. fun if alia 

 mut. nov. 



DESCRIPTION' OF STRUCTURE .VXD ORIGIN 



OF NEW VARIATION WITH NOTES ON ITS 



SIGNIFICANCE 



The most characteristic feature of 

 the new mutation which I am calling 

 Oe. Lamarckiana mut. funifolia, is the 

 strong revoluteness or downward curl 

 of the leaf margins, which in the best 

 developed examples causes the leaf to 

 have almost a cylindrical form. The 

 leaf tissue between the lateral veins 

 becomes more strongly contracted than 

 the veins thus giving the leaves an 

 appearance superficially resembling 

 that of a braided rope, as shown 

 in Figs. 8 and 9. Cross-sections of 

 the leaves of Oe. Lamarckiana and of 

 Oe. Lamarckiana mut. funifolia are 

 shown in Fig. 10. Associated with this 

 revoluteness of the leaf margins is an 

 irregular fine rugosity of the ventral 

 (con\ex) surface of the leaves which 

 gi\es the plants a markedly gra\'ish 

 aspect (Fig. 11). In most strongly 

 re\ohite specimens numerous small jiro- 

 tid)erances often occur on the ventral 

 surface of the lea\es, on either side of 

 the midrib (l-'ig. 12). A section of one 

 of these protuberances is shown in 

 Fig. 13, where it is seen to differ in 

 structure in no essential way from the 

 body of the leaf from which it arises. 

 There is also some modilication of leaf 

 outline, the k\nes being usually rela- 



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