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Oenothera Lamarckiana Mut. Velutina

Hugo DeVries
Botanical Gazette
Vol. 63, No. 1 (Jan., 1917), pp. 1-24
Stable URL: http://www.jstor.org/stable/2469212
Page Count: 25
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Abstract

I. O. Lamarckiana mut. velutina=O, blandina arose from my family of O. Lamarckiana mut. lataxsemilata among seeds of the third generation saved in ~9o4, in 3 specimens. Of one of these I cultivated a second generation and of one of the others 4 successive generations, embracing together over 3000 plants.2. All these plants were exactly alike with the exception of 4 mutants which constituted a new type, O. spiralis. The mutation coefficient was 0.1 per cent, or about the same as for O. rubrinervis and O. nanella, and much smaller than that for O. Lamarckiana. 3. For the appearance of the original mutation only one sexual cell needs to be mutated, since in combining with a normal gamete it may give rise to O. blandina, as is shown by the splitting of both the reciprocal crosses of this form with O. Lamarckiana. The splitting goes into nearly equal groups of specimens like O. blandina and of laeta. 4. O. Lamarckiana mut. velutina resembles the hybrids of the type of velutina so much as to be considered one of them. Among them it is the most like O. (Lamarckiana x O. biennis Chicago) velutina, without the marks of the second parental species, however. It is slender, with long internodes in the spike, and with flowers as large as those of O. Lamarckiana. 5. O. Lamarckiana mut. velutina is distinguished from its parent species in a very striking character. It has lost the property of producing about one-half of empty grains; almost all of its seeds contain healthy and well developed germs and germinate easily. This new quality is dominant over that of the parent. It is the same as in almost all the older species of the genus. 6. Moreover, O. mut. velutina is distinguished from O. Lamarckiana at least in one other dominant character, the smoothness of its leaves at the time of flowering. Secondly, it is distinguished in quite a number of characters, which seem to be more or less independent of one another, namely, slender stature, long internodes of the flower spike, narrow and longitudinally folded leaves and bracts, and cup-shaped flowers. Besides these, the richness in red color and the hairiness of all organs, especially in their youth, are very striking marks. 7. In crosses with those species which split O. Lamarckiana and some of its other derivatives into the twin hybrids laeta and velutina, the O. mut. velutina produces only hybrids of the velutina type. 8. In crosses with O. Lamarckiana and O. nanella, these forms are seen to be split by O. mut. velutina into twin hybrids, which correspond to the twins produced by other species with them, but which, of course, lack the characters of those other parents. The twins of O. blandina may be considered as pure laeta and pure velutina, therefore, the former having smooth leaves and bracts in the summer, the latter being identical with O. blandina itself. 9. The study of our new mutant reveals the existence of at least two recessive characters in O. Lamarckiana, namely, the bubbles of the leaf blade and the presence of typical empty seeds.