MUTATIONS OF OENOTHERA SUAVEOLENS DESF. 261 



to any study, although 1 observed the same phenomena in corres- 

 ponding crosses of some derivatives of Oe. Lamarckiana. Probably 

 they will afterwards yield the material for an analysis of the charac- 

 ters of Oe. suaveolens. Among the laeta the production of lutescens 

 was repeated but there were only 1 -{- -4- 3 = 4 of this type 

 among 3 x 70 = 210 plants. 



The progeny of the lutescens were uniform, almost yellow in their 

 first youth but becoming more green in the course of the summer. 

 They made their stems without first producing rosettes of radical 

 leaves, just as the Oe. mut. lutescens usually does, and had the broad 

 foliage and yellowish flower buds characteristic of this type. The 

 offspring of the velutina of 1915 constituted a uniform type with 

 almost linear leaves, conical flower buds and a striking hairiness 

 of all the organs, repeating thereby the characters of the seed- 

 bearer, and resembling almost exactly the velutina of the crosses 

 Oe. biennis x Lamarckiana and Oe. syrticola x Lamarckiana. In the 

 midst of August 1 had 24 large flowering specimens and 8 weak 

 rosettes with very long and narrow radical leaves. I compared them 

 with the velutina, which I cultivated at the same time from seeds 

 of my second cross, and found them identical. Moreover I got the 

 same types from the corresponding cross of Oe. suaveolens x Oe. 

 Lamarckiana mut. nanella, to be described elsewhere. See fig. 4. 



In the flowering specimens the petals were 4 cm. long, the stigma 

 elevated above the anthers, the flower buds thick (1 cm.), the fruits 

 more or less conical but thin, 3 cm. long. All organs were covered 

 with the gray hairs, which are so characteristic of the velutina type 

 in general. Leaves narrow, e.g., 4 x 13 cm. The plants reached a 

 height of about 2 meters and were richly branched. 



Apart from the appearance of specimens of mut. lutescens and 

 the variability in minor marks, we may conclude that Oe. suaveolens 

 behaves like Oe. biennis in its crosses with Oe. Lamarckiana. 



Oe. Lamarckiana mut. lata x Oe. suaveolens. — The conclusion 

 just reached may be strengthened by a study of this cross. In its 

 crosses with Oe. Lamarckiana this lata produces about 25 percent, 

 but in those with Oe. biennis about 50 percent of specimens of the 

 lata type (Gruppenweise Artbildung 1913, p. 251). I fertilized two 

 specimens of a culture of Oe. Lamarckiana mut. lata in the midst 

 of July 1913 and repeated the cross at the end of August on the 

 same spikes, using the pollen of the same specimens of Oe. suaveolens. 



The four cultures consisted in 1914 of the same two types, of 

 which one was an intermediate between lata and suaveolens, showing 



