MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 13 



the parental type, matures comparatively few seeds, and is dominated by the 

 parental characteristics in crossing, and it has survived in its original habitat 

 and blooming specimens have been observed there for twenty years in com- 

 petition with the parental form. 



The more important anatomical features of 0. brevistylis were described 

 by Pohl (1895), but it seems desirable that its general taxonomic aspect, as 

 presented in the cultures in New York, should be put on record. 



The rosettes are open, leaves ovate-spatulate, crinkled, the upper ones 

 approximately denticulate, bright, dark green, puberulent beneath, less so 

 above, conspicuous broad veins, petiole winged to near the base, much more 

 obtuse and rounded at apex than 0. lamarckiana. 



The adult shoot resembles O. lamarckiana, very closely, even in the form 

 of the stem-leaves. The bracts, however, seem slightly thinner and appear 

 somewhat broader than those of the parental type. 



The conic parts of the buds are 2 to 5 cm. long, appearing more cylindrical 

 than the parental form, and are covered with very short, spreading hairs. 

 The buds are distinctly tinged with red, and the free erect tips are unequal 

 and are not spreading. 



The petals are 45 to 50 mm. long and 40 mm. wide, being firm and more or 

 less deeply emarginate. The filaments are 2 cm. long, the anthers i cm. long 

 and slender. The pistil does not usually emerge from the tube of the hypan- 

 thium, the stigma being seen in the very throat of the flower. The stigmatic 

 lobes are very irregularly developed. 



But few capsules are matured. The capsules are 15 to 18 mm. long and 

 6 to 7 mm. in diameter at the base, being finely pubescent with a few spreading 

 hairs, bright green and slender, tapering slightly toward the apex. 



The hypanthium in this species bears about the same relation to the reflexecl 

 sepals as in the parental form (plate 3). 



OENOTHERA LATA. 



0. lata was first seen by De Vries in the plantlets produced by seeds har- 

 vested at Hilversum, Holland, in 1886, and brought into bloom in 1887, and 

 he has observed the origin of a total number of 493 as mutants in a progeny of 

 the parental type embracing 130,000 plants. 



It has been observed to arise in New York from the third generation of 

 a strain grown from seeds furnished by Professor De Vries, and also in seeds 

 obtained from Vilmorin in Paris. 



A sowing was made of seeds of O. lata X 0. lamarckiana, furnished by Pro- 

 fessor De Vries. This form is characterized by atrophied stamens which 

 produce only a few pollen grains, of fairly normal structure, which seem to 

 be incapable of producing fertilization ; but when the plant is pollinated by 

 0. lamarckiana, lata characters appear in the first generation as forming from 



