130 ANGIOSPERMAE—DICOTYLEDONES 



of the kind when it approaches a flower first touches the stigma and then separates 

 the united anthers, thus usually effecting crossing. Should insect-visits fail, automatic 

 self-pollination is now and then possible, owing to the close proximity of the anthers 

 and stigma just after the flowers open. Towards the end of anthesis, but not earlier 

 as a rule, the corolla falls off and the stigma is drawn between the anthers so as to 

 effect autogamy. 



Visitors. — Vide supra. Ducke and Graeffe observed the very long-tongued bee 

 Osmia macroglossa Gersl., as a frequent and exclusive visitor at Bozen, Schulz saw 

 a number of flowers perforated at the base by the humble-bee Bombus terrester L. 



1987. O. echioides L. (= O. Vaudense Gremli). (Briquet, ' £tudes de biol. 

 flor. dans les Alpes Occident.') — The flowers of this species are sulphur-yellow in 

 colour, smell like honey, and secrete abundant nectar from five little scales at the 

 base of the corolla. Briquet says they are visited by humble-bees, bees, and butter- 

 flies, which regularly effect cross-pollination. The horizontal corolla is 20-3 mm. in 

 diameter, and its entrance 5 mm. The long thin style projects 5 mm. from the 

 flower, and is surrounded by the anthers, which are laterally fused at their bases. 

 Kirchner states that, should insect-visits fail, automatic self-pollination can only be 

 brought about by fall of the corolla. 



Visitors. — Vide supra. 



612. Cerinthe L. 



Homogamous bee and humble-bee flowers ; with nectar secreted by the swollen 

 fleshy base of the ovary, and sheltered in the uppermost part of the pendulous 

 bell-shaped corolla. 



Kerner states that the peduncle bends down in late anthesis, causing the flower 

 to assume a nodding or pendulous position, and bringing the stigma into the line of 

 fall of the pollen, so that autogamy is inevitable. 



1988. C. alpina Kit. ( = C. glabra Mill>). (Herm. MuUer, ' Alpenblumen,' 

 pp. 264-6.) The pendulous flowers of this species are pollinated by humble-bees 

 with a proboscis at least 9 mm. long. These visitors cling to the corolla from 

 below, and insert their proboscis into its narrow opening. They first touch the 

 widely exserted stigma, and their proboscis then strikes against the anthers, by 

 which they are dusted with pollen. 



Visitors. — Herm. Miiller observed the humble-bee Bombus alticola Krchb. in 

 the canton Graubtinden. 



1989. C. minor L. (Herm. Miiller, ' Weit. Beob.,' Ill, pp. 9-14.) — In this 

 species the nectar is less deeply hidden than in C. alpina, so that bees with 

 a proboscis not less than 6 mm. long can reach the secreting base of the flower. 

 In doing this they hold on to the corolla-lobes with their first and second pairs 

 of legs, further supporting themselves by placing the hind ones on the same or 

 neighbouring flowers, or on the bracts. The anthers are borne on short stiff 

 filaments, and their tips are closely applied to the style, while their margins are 

 in contact. The base of each anther-lobe is produced into a filiform appendage, 

 which interlocks with the corresponding appendage of the adjacent lobe of the 



