Roberlson — Flowers and Insects. 153 



ized bees. The flowers are perfect and homogamous, but rare 

 cases of gynomonoecism and gynodioecism have been recorded 

 by Irmisch (2), Schroter (9), Calloni (10) and Schulz (11). 

 The perfect flowers are spontaneously self-pollinated after the 

 innermost anthers bave begun to dehisce (Kerner 12). 



Hepatica acutiloba DC. — H. acuta (Ph.) Britton. — The 

 plants are common on hill-sides and bloom quite early — March 

 18th to April 19. The scapes rise 1-2 dm. high and bear erect 

 flowers with about six sepals, which are blue, pinkish or white, 

 expanding horizontally so that the flowers measure about 25 

 mm. across. Commonly several scapes are near together, and 

 the plants, having no competitors to overshadow them, are 

 quite conspicuous. The flowers close at night and open in 

 the morning, the old ones persisting long enough to increase 

 the attractiveness of the patches. 



As stated above, H. triloba is considered to be without 

 nectar, and I could not satisfy myself of its presence in this 

 species either by sight, taste or test for sugar in water in which 

 the flowers had been immersed. In spite of the failure to dis- 

 cover its presence I am inclined to suspect that it occurs in a 

 thin layer, for all of the insects mentioned in the list thrust 

 their proboscides about the bases of the filaments, except 

 Syrphus americanus. On the other hand none of them were 

 feeding upon the pollen, or collecting it, except the three 

 Syrphidae and the hive-bee, which is not indigenous. The 

 receptacle is covered with papillae which may secrete nectar. 

 Unless they do, I can understand neither why they are present 

 and so strongly developed, why the filaments are separated 

 in such a way as to make room for them, nor the behavior of 

 the insects. In Anemone nemorosa, which is also said to be 

 devoid of nectar, Bonnier* states that similar papillae secrete 

 nectar in minute drops. 



The early flowers with their abundant exposed pollen, and 

 possibly convenient nectar, are adapted to the less specialized 

 bees, Andrenidae, though often also visited by Syrphidae 

 and other insects. With rare exceptions, the visitors consist 

 of a few individuals of the commonest insects flying at the 



* Les Nectaires, 141. 



