366 PROCEEDINGS OF THE ACADEMY OF [1892. 



CONTRIBUTIONS TO THE LIFE HISTORIES OF PLANTS, NO. 8. 

 by thomas meehan. 



Euphrasia ofe'icinalis. 



Mr. Darwin, in his interesting work on "Cross and Self-fertiliza- 

 tion of Flowers" (1877), places this pretty little plant in the list of 

 those which have " become modified so as to insure self-fertilization." 

 Some additional information on the subject makes it ^Yorth while to 

 go over the whole matter again. 



The flowers are so abundantly fertile that one would at once infer 

 that it is self-fertilized, but the apparently strong proterogynous char- 

 acter of the flower leads to a suspicion that this impression is wrong. 

 The curved style is projected beyondthecoroUabeforethelatterisfully 

 expanded, appearing like a folded thread of silk, completely closing 

 the mouth. The stigma at the end of the incurved portion is bent 

 down onto or under the anthers which present it with pollen before 

 the flower has fully expanded. So early is the flower fertilized that 

 the pistil, having fulfilled its function, dies away almost immedi- 

 ately after the mouth of the corolla fully expands. The flower pre- 

 sents the remarkable phenomenon of a pistil dried up almost as soon 

 as the corolla is fully open. It seems evident that the pistil 

 matures long before the stamens, but the curvature of the style 

 keeps the stigma in contact with the stamens so that it cannot escape 

 fertilization. If the pistil were projected in a straight line, as is 

 usual in flowers, it is more than likely that aid would be required in 

 securing pollination. It does look as if the expression quoted from 

 Darwin, that the flower had been modified to ensure self-fertiliza- 

 tion, is in this instance literally correct. 



Notes on Gaura and Oenothera. 



Although in a general way, flowers of some species of Gaura and 

 allied genera are known to open toward evening, and with some 

 suddenness, so far as I know, no details of the phenomenon have been 

 recorded. Having plants of Gaura biennis and of G. parviflora 

 within a hundred feet of each other, under nearlv the same condi- 

 tions, I spent a week previous to the 20th of August in closely 

 watching them, with the view of noting any difference in the 

 behavior of the two closely allied species. 



Having come to look on those plants that are abundantly fruitful 

 as self-fertilizers, I was at first struck with the exceptional fruit- 



