290 TRANS. ST. LOUIS ACAD. SCIENCE. 



Styled form is (in our wild plant, of which perhaps 1,000 indi- 

 viduals have been examined) wanting in O. violacea, while it is 

 more abundant than both other forms in O. Snksdorfii. Observa- 

 tions on the fertility of these species are lacking, but Mr. Darwin 

 has shown that the short-styled flowers of dimorphic Primulas 

 are most fertile,* and the same rule seems to apply to trimorphic 

 plants, with the single exception oi Lythrum saUcana^\ where the 

 mid-st)led is the most fertile form. It is, therefore, impossible 

 for us to draw any inferences from a comparison of the fertility 

 of the several forms with their relative abundance. 



In O. violacea the curve (2) representing the longest stamens 

 of long-styled flowers is depressed to about the same relative po- 

 sition as in O. Suksdorjii ; so that it is safe to say, that, aside from 

 differences depending upon the greater length of all the parts in 

 O. Suksdorjii, the diagrams of these two species would be essen- 

 tially alike, were the mid-styled form of O. violacea to be found 

 anywhere in abundance. 



There is doubtless a reason for the depression of the longer sta- 

 mens in long-styled flowers of these species, but it has escaped 

 me. While studying O. violacea, I fancied that it might be an 

 approximation of the two sets of anthers indicating an approach 

 to normal dimorphism ; but no such approximation is shown in 

 the short-styled flowers, as may be seen by comparing curves 4 

 and 5, and the occurrence of the same feature in O. Suksdorjii, 

 which, as has been shown, has the mid-styled as its predominant 

 form, entirely invalidates this conclusion. 



It is to be regretted that we have no reliable average data on 

 which to base comparisons with other trimorphic species of the 

 genus. The rose-purple species of the Southwest, which are re- 

 lated to O. violacea, and may be found to resemble it very closely 

 in their floral characters, are good subjects for the study of resi- 

 dent botanists ; and the botanists of Cincinnati, who have access 

 to an abundance of O. rectirva, may easily make the necessary 

 measurements for this species. It is also very desirable that some- 

 one who has access to enough individuals of the Californian and 

 southern creeping plant that I have called O. corniculata, var. (?) 

 niacrantha, should make an extendd series of measurements of 



• "Different Forms of Flowers," p. 20. f Darwin, 1. c. 357. 



