RANUNCULACEAE 17 



phaga camaria Z., nect-lkg. (Kn., Kiel ; H. M.) ; 15. Scatophaga merdaria F., po-dvg. 

 (H. M.); 16. S. stercoraria F., po-dvg. (Kn., Kiel); 17. Sepsis cynipsea Z. (Kn., 

 Fohr); 18. Thryptocera sp. (H.M.); 19. Small Muscidae (H. M.) ; {d) Syrphidae: 

 20. Chrysogaster viduata Z., skg. and po-dvg. (H. M.); 21. Eristalis arbustorum L. 

 (Kn.) ; 22. E. nemorum Z. (Kn.) ; 23. E. tenax Z. (Kn., all three po-dvg., freq., 

 Kiel ; H. M., po-dvg. or skg., feet abundantly smeared with pollen, so as to effect 

 cross-pollination when visiting a fresh flower) ; 24. Helophilus floreus Z. (H. M.), 

 and 25. H. pendulus Z., both po-dvg. (Kn., Kiel) ; 26. Melanostoma mellina Z., 

 po-dvg. (H. M.); 27. Syrphus sp., po-dvg. (Kn., Kiel). C. Hymenoptera. 

 Apidae: 28. Apis mellifica Z. 5, skg. and po-cltg., freq. (Kn., Kiel and Fshr; 

 H. M.); 29. Bombus terrester Z. 5, skg. (H. M.); 30. Halictus minutissimus K. 9, 

 po-cltg., isolated cases (H. M.) ; 31. H. sexstrigatus Schenck $, ditto (H. M.). 

 D. Neuroptera. 32. Psocus sp., nect-lkg. (Kn., Fohr). 



MacLeod, in Flanders, noticed Apis, Megachile, and Eristalis (Bot. Jaarb. 

 Dodonaea, Ghent, vi, 1894, p. 181). 



In Dumfriesshire (Scott-Elliot, 'Flora of Dumfriesshire') Muscidae have been 

 observed. 



36. B. divaricatum Wimmer (=Ranunculus circinatus Sibth.), according to 

 Kirchner, has the same flower mechanism as the last species. 



37. B. paucistamineum Sonder (=B.trichophyllum Chaix, in part). (Knuth, 

 ' Weit. Beob.,' pp. 227-8.) — This plant is very common on the North Frisian 

 islands of Nordstrand and Pellworm. The numerous flowers remain open even in 

 rainy weather, and so abundant and closely massed are the plants in these islands 

 that some ditches look as if they were covered with a white table-cloth. The diameter 

 of the flower is 12-13 ™™- Each petal is about 6 mm. long, and about 3 mm. 

 broad towards its tip ; the base is marked with a yellow nectar-guide, and is so narrow 

 that there is a considerable space between the individual petals. The plant is slightly 

 protogynous : in just-opened flowers the stigmas are partly mature, while the anthers 

 of the few stamens (usually only 8-12) are still closed. Their ripening goes on 

 centripetally, and the filaments of the 4-6 outer ones elongate, bending towards the 

 petals, so that insects alighting on the middle of the flower effect cross-pollination. 

 The filaments of the 4-6 inner stamens elongate later on, but remain with their 

 dehisced anthers above the stigmas — now very markedly papillose — upon which 

 pollen necessarily falls, thus effecting self-pollination automatically. This must 

 be effective, for all the carpels constantly mature, though I have not observed any 

 insect-visits, despite long watching during favourable weather. 



38. B. (Ranunculus) paucistamineum Tausch (not Sonder) was found 

 by Schulz — in central Germany — to be either homogamous or slightly protandrous, 

 with very great variation in the size of the flowers and the number of stamens. He 

 also observed gynomonoecism. According to Wamstorf (Schr. natw. Ver., 

 Wernigerode, xi, 1896), the flowers at Neuruppin are protogynous, and their 

 diameter is 10-17 mm. They possess as many as 15 stamens, which are shorter 

 than the head of carpels. Pollen : golden yellow, roughly tuberculate, varied in 

 form, ellipsoidal or bluntly conical, with three longitudinal furrows, 30-43 y. long 

 and 25-30 /A broad. According to Freyn, the submerged flowers are sterile. 



39. B. fluitans Wimmer (=Ranunculus fluitans Lmk.). — According to Freyn, 

 this is usually sterile because the flowers are submerged. The fruits were set, 



DAVIS. II 



