1 6 MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 



are sometimes distinctly reddish. The laminae are shining green above, more 

 or less puberulent on both surfaces, and obscurely denticulate. 



The adult plant is less than i meter in height and is very sparingly branched 

 below, with a few very short branches above. The basal branches are ascend- 

 ing and do not reach above half the height of the stem. The stems are 

 strongly channeled and angled. 



The stem-leaves are crowded, hang down, and are pubescent on both sur- 

 faces, 7 to lo cm, long, oblong-elliptical, remotely and shallowly toothed, 

 acutish or obtuse at the apex, and irregularly narrowed into a short margined 

 petiole. The laminae are strongly crinkled, dark green, and become tinged 

 with crimson with age. 



The bracts are oblong or ovate-oblong, acute at the apex, cordate or sub- 

 cordate at base. The buds are reddish, the conic portion being about 2 cm. 

 long and finely pubescent with short spreading hairs and a few longer ones. 

 The free erect tips are about 3 to 5 mm. in length. The petals are thin, 

 generally crinkled, somewhat emarginate and crenate, and are 3 cm. long and 

 4 wide. In the unfolding of the flower the petals open only so far as to form 

 a cup-shaped corolla. The hypanthium is about 3 cm. long, slightly longer 

 than the calyx-lobes. The slender ovary is about 8 mm. long. The filaments 

 are 15 mm. long and the anthers 8 mm. The pistils are slightly longer than 

 the stamens, the stigmatic lobes being about 5 mm. in length. 



The capsules are 22 to 26 mm. long and 6 to 7 mm. in diameter at the thick- 

 est part, finely pubescent, slightly angled and shining green, tapering slightly 

 to the apex (plate 6). 



OENOTHERA ALBIDA. 



O. albida was first recognized by De Vries as a mutant in 1888 and was 

 brought into bloom in 1896. It is distinguishable even in the earlier stages 

 by the paler color of the leaves, which in the rosettes have upturned margins 

 and are variously twisted. Seventeen examples appeared in the cultures 

 previously described during 1905, of which 6 were mutants from . lamarckiana 

 as found introduced on Nantucket. The following taxonomic characters 

 were observed : 



Seedling about 3 months old: Rosettes 15 to 17 cm. in diameter, thin, 

 somewhat raised above the slender rootstock; leaves 7 to 10 cm. long, 2.5 to 

 3 cm. wide, erect-spreading, the apex recurved and nearly touching the 

 ground; blades 5 to 7cm. long, oblong, broadest at about the middle, acutish 

 or mostly obtuse at the variously rounded apex, gradually tapering into the 

 almost translucent, margined petiole, pale light green, very thick and brittle, 

 margins undulate-denticulate, some of the 3^ounger leaves strongly wrinkled 

 on the margins. About 2 months later the rosettes were irregular, leaves 

 twisted and various-erected, convexed upwardly, pale yellowish-green, approx- 



