MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 1 7 



imately denticulate, oblong, soft-hairy on both surfaces, petioles winged half- 

 way to base. 



The adult plant was seen to be irregularly branched, the branches often 

 exceeding the main stem in length, which never reached a height of a meter. 

 Stem zigzag, rather stout, channeled and angled, branching mostly at base, both 

 branches and stems very brittle. Branches and stems hirsute, with spreading 

 hairs and closely pubescent. Internodes short, with the leaves crowded. 



Stem-leaves oblong to oblong-lanceolate, more or less regularly denticulate, 

 mostly obtuss or acutish. nearly sessile, tapering at base, finely pubescent 

 on both surfaces, very brittle and somewhat crinkled. 



The bracts are oblong, acutish, or obtuse, slightly clasping, subcordate, 

 erected when young, reflexed when mature, margins upturned. 



The buds are distinctly reddish, 3 cm. long, finely pubescent, with spreading 

 hairs and the free tips erect and 6 mm. long. 



Hypanthium 4 cm. long, slightly longer than the sepals. Petals thin, 

 35 to 40 mm. long, and 40 to 50 mm. wide, reflexed from the middle, deeply 

 emarginate at the apex. Filaments 2 to 3 cm. long, anthers 12 mm. long. 

 Pistils longer than the stamens, with the stigmatic lobes 5 mm. in length. 



Capsules 35 mm. long and 5 to 6 mm. in diameter at thickest portion, finely 

 pubescent and reddish, tapering slightly to apex. It is noticeable that com- 

 paratively few capsules are matured by this species. The terminal rosettes 

 are symmetrical and the buds erect and prominent (plate 5, b, and plate 7). 



HYBRIDIZATION OF A MUTANT AND ITS PARENTAL TYPE. 



In order to test the results which have been presented by Professor De Vries 

 with respect to the behavior of mutants in hybridization, a number of flowers 

 of 0. lamarckiana were castrated early in order to avoid entirely any proba- 

 bility of self-pollination, and these flowers were pollinated from unopened 

 buds of 0. ruhrinervis. The resulting capsules were harvested early in Sep- 

 tember, 1904, and sown in sterilized soil in the greenhouses in November, 1904. 

 Early in January the seedlings were large enough to make the separate types 

 discernible, and the task of discarding the duplicates was begun. The entire 

 progeny was found to include 90 of lamarckiana (and one of its mutants, of 

 which I was present) and 221 rubrinervis. The ruhrinervis, which is to be 

 regarded as a progressive mutant of latnarckiana, has been seen to surpass it in 

 vegetative vigor and rapidity of growth, besides producing seeds quite as 

 plentifully, and is sometimes dominant when crossed with the parent. Thus 

 De Vries found that when the above cross was made he obtained 19, 24, 68, 

 and 74 per cent of rubrinervis in four different lots, giving an average of 

 totals of 46 per cent rubrinervis produced in such crosses. The culture 

 described above yielded 71 per cent rubrinervis. 



