i8 ANGIOSPERMAE—DICOTYLEDONES 



however, in herbarium specimens, which were obtained from eastern Schleswig- 

 Holstein, and from the island of Rom. 



40. B. carinatum Schur. — Freyn states that the very long peduncles — 

 which are at right angles to the surface — are not submerged by the rising of 

 the water. 



41. B. Baudotii d. B.— 



Visitor s.^Verhoeff observed one of the Muscidae in Norderney (Anthomyia sp., 

 skg., one instance). 



10. Ranunctilus L. 



Flowers homogamous or — more rarely — slightly protogynous or protandrous, 

 with nectar half concealed. Insects are attracted by the petals, which are usually 

 yellow, but white or red in a few species. At the base of each petal there is 

 a nectar-pit, that is either upwardly prolonged into a membranous scale (in the 

 species with white or red flowers), or (in most yellow-flowered species) covered 

 by a fleshy upwardly directed scale, or else it is open (in R. sceleratus, and — 

 according to Almqvist — in a few northern species (R. pygmaeus Wg., R. hyperboreus 

 Rotlh., R. nivalis Z.)). Many species have flowers that repeatedly open and close. 

 On dehiscence of the anthers the stamens incline towards the petals, so that the 

 pollen falls upon these, but not so readily upon the stigmas. Only the larger nectar- 

 sucking, pollen-collecting, or pollen-devouring insects come regularly into contact 

 with the stigmas, effecting self- or cross-pollination with equal ease. The larger 

 the flowers the less likely is automatic self-pollination, for with increased size the 

 distance between anthers and stigmas of course becomes greater, and there is less 

 chance of pollen falling upon the stigmas when the blossoms are bent by the 

 wind or any other agency. But as increase of size in the flowers furthers the visits 

 of insects — with resultant pollination — this disadvantage is counterbalanced. 



The flowers are sometimes gyno-monoecious, while according to Schulz, gyno- 

 dioecism occurs in R. acris, auricomus, hybridus, and repens, and the same condition 

 has also been observed in England by Whitelegge in the case of R. bulbosus. 



42. R. glacialis L. (Ricca, ' Oss. suUa fecondaz. incroc. d. veget. alp. 

 e. subalp.' ; Lindman, ' Bidrag till Kanned. om Skand. fjellvaxt. blom. o. befrukt.' ; 

 Herm. Miiller, 'Alpenblumen,' pp. 128—9; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II; 

 Andersson and Hesselman, ' Bidrag till Kanned. om Spetsbergens o. Beeren Eil. 

 Karlvaxtflora.') — The flowers are homogamous or — according to Ricca — slightly 

 protandrous. In the Scandinavian highlands they are markedly protandrous. Some 

 may be female only. In old flowers automatic self-pollination can easily be effected 

 by the fall of pollen from the anthers of the inner stamens upon the stigmas. In 

 the Alps the size of the flower varies greatly (12-30 mm. in diameter). The structure 

 of the nectaries is equally varied (see Fig. 5). Besides hermaphrodite blossoms, 

 Kerner observed pseudo-hermaphrodite pollen flowers. He also found two forms 

 of hermaphrodite flower, corresponding to those of Anemone alpina. Andersson 

 and Hesselman state (op. cit., p. 42) that this species was frequently found in flower 

 in Spitzbergen during July. 



Visitors. — Miiller observed — in the Alps — 2 flies and 2 micro-Lepidoptera. 



