402 BOTANICAL GAZETTE [December 



sist of quite a number of subspecieS; of which I collected over a dozen 

 in Kansas, JMissouri, Illinois, and elsewhere, during the summer of 

 1904. On sowing them in my experiment garden, I observed them 

 to be fairly distinct, each constituting a sharply defined type- The 

 form which is the most common throughout the United States is not 

 the same as the one introduced into Europe, neither for O. biennis 

 nor for O. muricata, as has also been pointed out by MacDougal 



for O. biennis. 



All these numerous elementary species agree with one another in a 

 most interesting character. Their anthers touch the stigma, open 

 themselves in the bud, and oroduce fertilization before the flower 



opens, 

 admitted 



finished 



very 



do occur, since I collected the hybrid of O. muricata and O. biennis 

 in the dunes near Amsterdam, and even more than once. A simple 

 means of pure self-fertilization may be derived from this pollination 

 within the bud. I cut the buds of our O. biennis one or two hours 

 before opening, cutting through the middle of the tube, and the pods 

 developed as strongly and produced as many good seeds as those whose 

 flowers were allowed to be visited by bees. The flowers of O. Lamar cH- 

 ana, O. Hookeri, and other large-flowered species, on the contrary, 

 are not fertilized in the buds, but are in need of the help of insects 

 (moths, bees, and bumble-bees). 



The specific hybrids of this group of Onagra differ in a very con- 

 spicuous way from ordinary hybrids in so far as the reciprocal forms 

 often are not identical, but differ widely from one another.^ Although 

 I have observed this fact in numerous cases, it is not a general rule. 

 The hybrid O. Lamar cManaX gi gas is identical "vvath O. gigasX 

 Lamarckiana, In the same way the species of the subgenus Euoeno- 



those of Onagra yield uniform hybrids. I crossed 

 th O. biennis. O. muricata. and O. Lamarckiana 



with 



the O. Sellowii with O. biennis^ O, muricata, and 

 and observed their reciprocal hybrids to be identical. 



Within the group of the Onagras, however, the reciprocal hybrids 

 are in most cases different, and with a few excentions are more similar 



to their 

 clinous. 



They are, as it is called, patro- 



wi 



a Die Mutationstheorie 2:471. 



<,^ 



