94 PROCEEDINGS OF THE ACADEMY OF [1899. 



immature fruit, which has fallen, after being fairly fertilized, hy 

 the failure in the stock of nutrition to bring them to perfection. In 

 the carefully noted observations of Mr. Darwin and others in the 

 Old World, on the fertilization of flowers, failure of nutrition is 

 rarely permitted to account for the failures to seed in many of the 

 experiments noted. 



I have for some time past concluded that, in some manner not 

 yet demonstrated, pollen tubes may and do at times reach the 

 ovules otherwise than by way of what we commonly know as the 

 receptive portions of the stigma. In Viola tricolor this may occur 

 by way of the filmy hair on the dorsal part of the stigma, which 

 the pollen may reach in this species as already noted, and the ques- 

 tion may arise as to what is the stigma proper in Viola. It is 

 customary to regard the small opening at the apex of the thickened 

 style as the stigma. I am inclined to regard it rather as a necta- 

 riferous gland. In examining flowers of Viola cucnllata, just 

 before they expand, the orifice of this tube is closed. When 

 the flower is examined the day following the opening, a globule of 

 very sweet nectar occupies the position; the following day this 

 disappears, and the hollow cavity noticed by various authors is 

 evident under a good lens. This open passage is hardly consistent 

 with the general character of a passage way for a pollen tube 

 which has to depend for material in building up its structure on the 

 cellular matter which it meets with on its journey to the ovule. 

 Nor can I recall any instance in which such a large proportion of 

 nectar is secreted by the receptive point of a stigma. On the other 

 hand, if we believe, as we undoubtedly may, that nectariferous 

 glands are atrophied primary structures, it will be difficult to trace 

 the morphology of such a gland situated in the position this occu- 

 pies. 



But the morphology of the violet presents some anomalies. 

 Though it is certain, as I have demonstrated in various papers, that 

 the leaf does not always originate from the node from which it 

 seems to spring, and that it is the union of the edges of the leaf-blade 

 that causes what we know as decurrence in stem structure — it does 

 not follow that decurrence is not sometimes really de-curreuce. In 

 many species of Lactuca from the south of Europe and eastern 

 Asia, this is evidently so ; and in Viola the auricles at the base of 

 the sepals would undoubtedly h;ive to be accounted for in any fair 



