358 



ANGIOSPERMAE—DICOTYLEDONES 



843. R. Chamaemorus L. — This species is dioecious. The white flowers 

 appear to be visited but seldom, as fruits are rarely seen. According to Wanning, 

 propagation is largely effected by underground shoots. Vahl says that in some parts 

 of Greenland female plants alone occur, and in other parts only males. This state- 

 ment is confirmed by Andersson and Hesselman (' Bidrag till Kanned. om Spets- 

 bergens o. Beeren Eil. Karlvaxtflora,' p. 18). Such an arrangement is intelligible as 

 a result of the marked vegetative reproduction. 



In Spitzbergen the species is usually sterile. Female flowers only were seen 

 there in bloom (7. 8. '83 and 23. 7. '98), but no fruits were observed (Andersson and 

 Hesselman, loc. cit.). 



Schulz states that female flowers with almost normal stamens are found in the 

 Riesengebirge. 



Visitors. — Schneider observed the humble-bees Bombus alpinus Z. and B. 

 scrimshiranus K. in Arctic Norway (Mus. Aars. Troms0, xvii, 1895). 



In Dumfriesshire an Empid and 3 Muscids were recorded (Scott-Elliot, ' Flora 

 of Dumfriesshire,' p. 57). 



Fig. 113. ^«^.s arc/i'c«.s, Z.. (after E. Warming). A. A flower seen from above. B. Longitudinal 

 section through a flower; the outermost anthers are ripe. C, D, E. Stamens of different series. E. An 

 outermost one. F. A carpel. 



844. R. arcticus L. — According to Warming's investigations at Bosekop 

 (Norway) the dark rose-red stellate flowers of this species are slightly protandrous 

 (' Arkt. Vaxt. Biol.,' pp. 37-40). The outer anthers dehisce early, and the stamens 

 are more closely crowded together above the stigmas than in other species of the 

 genus, so that automatic self-pollination necessarily takes place. Propagation is 

 chiefly effected by subterranean shoots. 



845. R. serpens Weihe. — 



Visitors. — Loew saw Apis (skg. and po-cltg.) in the Berlin Botanic Garden. 



246. Dryas L. 



Flowers white ; protogynous, homogamous, or protandrous ; with concealed 

 nectar, secreted by a fleshy ring internal to the insertion of the stamens. Not rarely 

 androdioecious or andromonoecious. 



846. D. octopetala L. (Ricca, Atti Soc.ital.sc. nat., Milano, xiv, 1871 ; Herm. 

 Miiller, ' Alpenblumen,' pp. 227-8; Schulz, 'Beitrage'; Lindman, 'Bidrag till 

 Kanned. om Skandin. Fjallvaxt Blomn. o. Befrukt.' ; Warming, ' Arkt. Vaxt. Biol.') — 



