GENTIANEAE 



103 



The following were recorded by the observers, and for the localities stated. 



Herm. Miiller, 2 humble-bees Bombus agrorum F. 5 (proboscis 12-15 mm.) 

 and B. muscorum F. 5 (proboscis 11-15 mm.), both freq., skg., Schulz (Halle), 

 numerous flowers perforated by humble-bees. Kerner, small beetles using the 

 flowers as a refuge. Alfken (Bremen), the bee Halictus flavipes F. 5, po-cltg. H. de 

 Vries (Netherlands), the humble-bee Bombus agrorum F. 5. 



1901. G. acatilis L. (Herm. Miiller, ' Alpenblumen,' pp. 332-6; Ricca, Atti 

 Soc. ital. sc. nat., Milano, xiv, 1871; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 

 163, 198, including G. excisa Presl.) This species bears protandrous odourless 

 humble-bee flowers (' revolver flowers ' of Kerner), in which self-pollination is usually 

 excluded. Kerner says that they become pendulous in unfavourable weather, so that 

 pollen which falls out of the anthers is guided to the stigma along the furrows 

 between the folds of the corolla, thus eff'ecting automatic self-pollination. According 

 to Hermann Miiller, opening and closing are not dependent upon increase and 

 decrease of light, but of heat. Kerner states that the flowers open about 7-8 a. m., 

 shutting again about 6-7 p. m , 



Fig. 262. Gentiatia verna^ L. (from Henn. Miiller's ' Alpenblumen '). A. Flower seen directly from 

 above. B^ C. Upper and lower parts of longitudinal section of flower. D. Similar section through 



upper part of flower, with anthers at a higher level than in B. a, anthers ; co, corolla ; f, ligoles ; ^, filaments ; 

 jfr, style ; , nectary ; ov, ovary ; s/, stigma. 



Visitors. The following were recorded by the observers stated. 



Herm. Miiller, 8 bees (including 5 humble-bees), 3 Lepidoptera, a fly, and a 

 beetle, though only the humble-bees are effective pollinators. Ricca, humble-bees 

 effecting pollination. Herm. Miiller found 90 % of the flowers perforated by 

 Bombus mastrucatus Gers/. Kerner saw small beetles using the flowers as a refuge. 



1902. G. angustifolia Michx., and 1903. G. Clusii Perr. et Song. ( = G. 

 acaulis Z., according to the Index Kewensis). These species both bear 'revolver 

 flowers ' in which, according to Kerner, autogamy can take place as in G. acaulis. 



