164 



ANGIOSPERMAE—DICOTYLEDONES 



possibility of automatic self-pollination is apparently not precluded. Plants observed 

 by Warming in the Scandinavian highlands were also strongly protandrous, as were 

 those examined by Schulz in the Tyrol. The latter describes the plant as gynodioe- 

 cious, rarely gynomonoecious, very rarely androdioecious or andromonoecious. 



Visitors. — Loew observed the following in Switzerland (' Beitrage,' p. 60). — 



Diptera. Bombyliidae : i. Argyromoeba sinuata i^a//.; 2. Bombylius minor Z. 



Herm. Mtiller — in the same country — saw numerous Lepidoptera, especially 

 ■Noctuidae, and flies ; also some bees. 



A. Schulz observed a similar circle of guests in the Tyrol. 



MacLeod noticed a Muscid in the Pyrenees (Bot Jaarb. Dodonaea, Ghent, iii, 

 1591. P- 375)- 



Fig. 4g. SiUne rupestris, L. (after Herm. MuUer). A, Flower in the first (male) stage. B. 

 Pistil of the same flower with the branches of the style still closely apposed, and stigmas not yet mature. 

 C, Flower in the second (hermaphrodite) stage. D. Flower in the third (female) stage. 



411. S. acaulis L. (Herm. Mtiller, 'Fertilisation,' p. 129, ' Alpenblumen,' 

 pp. 194-7; MacLeod, Bot. Jaarb. Dodonaea, Ghent, iii, 1891, pp. 375-6; Ricca, 

 Atti Soc. ital. sc. nat., Milano, xiii, 1870.) — This species is trioecious. The markedly 

 protandrous hermaphrodite red flowers are crowded together in great numbers, and 

 are visited by so many insects that there is scarcely any or no necessity for automatic 

 self-pollination. In some places, however, none of the flowers are bisexual (Schulz, 

 Warming). Ekstam says that in dioecious plants in Nova Zemlia the diameter of 

 red or white corolla is 6-12 mm. The only unisexual flowers there observed were 

 male ; the bisexual ones were — as elsewhere — protandrous. 



According to Andersson and Hesselman (' Bidrag till Kanned. om Spetsbergens 

 o. Beeren Eil. Karlvaxtflora '), this species flowers in Spitzbergen from the beginning 

 of July to the end of August ; during the latter month fruits are regularly ripened. 



