MUTANTS AND HYBRIDS OF THE OENOTHERAS. 1 3 



flowers and flower-buds. Both types are to be found in the plants coming from 

 the seeds, as well as in those grown from the roots you sent me. The differences 

 are slight, but striking, absolutely individual, and without transitions. Most of 

 the individuals have broader linear petals and comparatively more rounded 

 flower-buds. The others have narrower and therefore more strictly linear 

 petals, and thicker buds. 



I have also sown seed I got from Prof. B. L. Robinson, of Harvard Univer- 

 sity, gathered at Jeffrey, N. H., under the name of O. cruciata. They are wholly 

 different' from yours, being more slender, less nutating, and with a strikingly 

 longer calyx-tube. 



The same facts are given in ' ' Species and Varieties : Their Origin 

 by Mutation " (De Vries, 1905, p. 589), in which it is also stated that 

 " It seems not improbable that 0. cruciata includes a group of lesser 

 unities, and might soon prove to comprise a swarm of elementary 

 species, while the original strain might even now be in a condition of 

 mutability." 



The cultures of 1904 included over sixty specimens of 0. cruciata 

 which reached the adult stage, and included not only the two forms 

 which he had observed to arise from the seeds and roots sent him from 

 this place, but also the third obtained only from material from New 

 Hampshire. It is obvious, therefore, that one form arises spontane- 

 ously from one of the other two forms suddenly, and dried specimens 

 from the crop of 1903 in the New York Botanical Garden show that 

 it originated in this manner here in the first year of cultivation, 

 although the second half of the same lot of seeds sent to Professor De 

 Vries failed to give rise to it in Amsterdam. 



The evidence at hand therefore seems to confirm the suggestion 

 as to the mutability of the species, but nothing may be said as to which 

 of the types constitutes the parent. The characters of the forms are 

 as follows : 



No. 1 (PI. VIII) .—Adult plant robust and luxuriant. Stem 1 to 

 1.5 meters tall, copiously branched, the branches spreading, sparingly 

 hirsute, the hairs rather ascending, 1.5 to 2.5 dm. long on the lower 

 part of the stem ; blades narrowly spatulate, finely toothed near the 

 apex, coarsely and somewhat doubly toothed below the middle, each 

 narrowed into a short semi-terete petiole, those of the upper cauline 

 leaves oblong-lanceolate to lanceolate, sessile, all more or less pubes- 

 cent about the veins beneath ; bracts oblong-lanceolate, about one-half 

 as long as the hypanthium, truncate at the base ; conic portion of the 

 buds slender, 16 mm. long, or somewhat longer, sparingly pubescent, 

 the free tips of the sepals 4.5 to 5 mm. long; hypanthium slender 

 terete or nearly so, 30 or 32 mm. long, becoming glabrous, about 4 mm 

 wide at the mouth ; sepals 17 to 20 mm. long, linear-lanceolate, about 



