J 



378 PROCEEDINGS OF THE ACADEMY OF [1892. 



a month later, no bipetalous flowers were noticed, but the same fer- 

 tilization in the unexpanded flower occurred. The Maine j^lauts 

 have a more zigzag habit of growth, and the leaves are more den- 

 tate (in many cases pinnatifid), than in the Atlantic City plants. 



Hypericum ellipticum. 



Generic characters, like those of species, are often found running 

 so close together that it is difiicult to draw a dividing line. No one 

 would question the propriety of separating Ascyrum and Hyperi- 

 cum : Ascijrum, "sepals four, very unequal ;" Hijpericum, " sepals 

 five, somewhat equal." In this species there are really but four 

 sepals, but a minute bract does duty as a fifth sepal. The sepals are 

 almost as unequal as those of any species of A-^curum could be. 



Teifolium hybridum. 



So much has been said of the relations between insects and the 

 flowers of clover that more would seem superfluous, but of Trifolium 

 hybridnm, the Alsike or Swedish clover, few observations have been 

 specially recorded. Of late years this species has become common 

 on Mt. Desert Island, at least it is very common about Seal Harbor, 

 where the unusual beauty and fragrance of the flowers press it 

 closely on our attention. Observing that every flower seemed fer- 

 tile, I anticipated self-fertilization, and found that this was the case. 

 In the unopened bud, just before the expansion of the petals, the 

 stamens and pistils are of equal length. The anthers press closely 

 against the stigmatic surface of the pistil and discharge the pollen 

 therein before the flower opens. After expansion the flattened keel 

 presses and keejis pressed together the stamens and pistil, prevent- 

 ing any exposure at any time. The stamens and pistil remain thus 

 entombed through life, dying eventually in each other's arms. If an 

 insect or the thumb nail be pressed against the base of the keel the 

 pistil and stamens are set free, but only to expose the pollen-covered 

 stigma. Many species of plants have their stamens and pistils so 

 arranged that, tliough close fertilization is the rule, the use of for- 

 eign pollen is not an absolute impossibility, though, when we con- 

 sider how few seeds of a crop ever get a chance to grow again, 

 the physiological value of an occasional cross on a seed Avhich has 

 small chance of ever growing is not apparent. But even this 

 chance is lost to this species of clover as found growing here in 

 July, for the abundant fertility is certainly due to self-pollination, 

 and cross-fertilization is wholly out of the question. Bees do not 



