162 PROCEEDINGS OF THE ACADEMY OF [1892. 



I have little doubt but that any annual may be made perennial 

 by persistently destroying the flower buds as they appear. When 

 we see in a state of nature, some few plants survive while numbers 

 perish the season of their birth we may reasonably look for 

 some circumstances which in these plants led them to bear seeds less 

 profusely than others, or to some other condition which aided 

 the vegetative in its struggle with the reproductive forces. 



On Self-pollination in Amsonia Tabern^montana. 



To ray mind the number of plants Avhich have their flowers con- 

 structed for self-fertilization is so large, that it would seem hardly 

 worth particularizing them but for the industrious work of noting 

 the opposite characteristics which prevails in our scientific serials. 

 It seems not fair to true science that only one side of nature's story 

 should be told. This is why I record some self-fertilizing cases. 



It has been left to me to point out that only those plants which 

 have other means of persistence than by seeds, have flowers which 

 are wholly dependent on external agents for pollination, — and also 

 to show that while flowers which have arrangements for self-fertiliza- 

 tion are abundantly fertile, those which cannot make use of pollen 

 without assistance, are frequently barren, and are at a sad disadvan- 

 tage in making their way through the world. So clearly has this 

 been worked out to my mind, that when a plant is found abundantly 

 fertile, it is fair to assume that it must be arranged for self-pollina- 

 tion. In Asdepiadacece, with the large majority of the floAvers 

 barren, we may theoretically assume insect agency, — with many 

 abundantly fertile Apoeynacece, Ave may assume self-fertilization. 



I have already shown than the Madagascar periwinkle, Vinca 

 ronea, with every flower fertile in American gardens, is a 

 self-fertilizer. Another of the same order, Amsonia Tabernce- 

 viontana, (the form known as A. sallcljolia Pursh), is abundantly 

 fertile. I watched the flowers this season, satisfied that they would 

 be found arranged for self-pollination. The plants proved, as usual, 

 abundantly fertile. On one panicle there were twenty-nine pairs 

 of follicles that matured ; there were many others that had been evi- 

 dently fertilized, but failed to reach maturity through lack of 

 nutrition. 



Showy as the blue flowers are, and we might suppose in view of 

 prevailing speculations, made so in order to be attractive to insects, 

 the arrangements are such that no insect, not even the ubiquitous 



