56 MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 



PEDIGREE-CULTURES OF OENOTHERA GRANDIFLORA, O. BIENNIS, AND 

 O. CRUCIATA. 



In order to test the mutative capacity of other evening-primroses, seeds 

 were obtained from correspondents in various parts of the world and as many 

 as 40 sowings were made in one year from 0. biennis. In only one strain, 

 however, did anything come to light which would be of interest in connection 

 with the chief purpose of these investigations. 



Parental individuals were selected and verified by Dr. N. L. Britton in 1903, 

 and from the seeds furnished by them the plants were grown which furnished 

 material for the descriptive diagnosis published in a previous paper (Mac- 

 Dougal, Vail, Shull & Small, 1905). This is not the species growing wild in 

 Europe and cited by De Vries in his "Mutationstheorie." 



Inflorescences of 4 separate individuals were inclosed in transparent paper 

 bags in such manner as to secure pure fertilization and the seeds preserved in 

 separate packages. Sowings were made in pans of sterilized soil, in accord- 

 ance with the usual custom, early in January, 1905. 



A number of seedlings were seen in which the first foliage -leaf and all suc- 

 ceeding leaves were very much narrower than the parental type. Sixteen 

 individuals of this kind were found and preserved, appearing in the progeny 

 of all of the 4 parents represented. An exact count of the number was kept 

 only in the case of one parent, No. 8.17, in which 4 of these aberrants were 

 included in a progeny of 669 individuals and formed very nearly 0.6 per cent 

 of the entire number. 



The aberrants retained their property of forming narrow leaves, which were 

 slightly paler in color than the parental type, and appeared to taper gradually 

 at the base into long petioles. One aberrant of 8. 17 gave off a lateral branch 

 at the base of the stem which developed broader leaves resembling those of 

 the parent. With the completion of development, the form of the capsules 

 and the entire habit of this branch were in exact duplication of O. biennis. 



On July 2 one of the aberrants opened a flower which also showed some 

 departures from the normal, being characterized by the extremely long sta- 

 mens and by the elongated capsule, which was of equal diameter throughout 

 and did not taper to a point or toward the tip as in its parental form. The 

 first 4 flowers which were brought to maturity on a lateral branch were inclosed 

 in a bag and self -pollinated. The seeds formed were allowed to mature and 

 these were sown as soon as practicable in order to determine the constancy 

 of the new form. 



The adult plant has a main stem varying from 80 to 150 cm. in height, and 

 branches freely from the base upward. The lower branches are long, slender 

 and assurgent, while the upper ones are much shorter. Numerous secondary 



