200 ANGIOSPERMAE—DICOTYLEDONES 



larger flowers automatic self-pollination readily takes place ; in the smaller it is 

 sometimes possible. Andersson and Hesselman state that this species flowers in 

 Spitzbergen from the middle of July till the end of August {' Bidrag till Kanned. 

 om Spetsbergens o. Beeren Eil. Karlvaxtflora'). Fruits were observed to be set, 

 though in an irregular fashion. According to Ekstam (' Bliitenbiol. Beob. a. Spitz- 

 bergen,' p. 26), the flowers are homogamous and 12-15 mm. in diameter. The 

 anthers bend towards the stigmas during dehiscence, so that self-pollination easily 

 takes place. 



Visitors. — H. Miiller (' Alpenblumen,' p. 190) observed Diptera (3 Muscidae 

 and a Syrphid) and a Lepidopterid in the Alps. On the Dovrefjeld large and 

 small Diptera and a Lepidopterid were also noticed by Lindman. Ekstam saw 

 Diptera in Nova Zemlia, and on five occasions in Spitzbergen (large and small flies). 

 In the latter island Holmgren observed Hymenoptera — Hemiteles septentrionalis 

 Holmgr., and Orthocentrus pedestris Holmgr. — as well as Diptera — Aricia (Spilo- 

 gaster) dorsata Zett., A. (S.) denudata Holmgr., A. (S.) megastoma Bohem., and 

 Sciara atrata Holmgr., very freq. 



496. C. Edmonstonii (Wats.) Murb. et Ostenf. — Andersson and Hesselman 

 state (■ Bidrag till Kanned. om Spetsbergens o. Beeren Eil. Karlvaxtflora,' pp. 59-61) 

 that this species begins to flower in Spitzbergen somewhat earlier (the second half 

 of June) than the last species, but ripens its fruits at the same time. The variety 

 caespUosum Malmgr. also flowers early. The diameter of the flower varies from 

 9-5 to II mm. There are both hermaphrodite and female blossoms, the former 

 being protogynous, homogamous, or protandrous. In all fully-developed flowers 

 autogamy is possible by contact of the coiled reflexed stigmas with the dehisced 

 anthers. The pollen-grains are very sensitive to damp, and at once burst when 

 placed in distilled water. Transitional forms between hermaphrodite and female 

 flowers are variable in number, and the latter set fruits irregularly. In one case 

 only twelve per cent, of the last year's blossoms — of which remains were present — 

 had done so. 



497. C. uniflorum Murith. (=C. subacaule Hegetschw., and C. glaciale Gaud.). — 

 Kirchner (' Beitrage,' pp. 15-16) describes as follows the mechanism of flowers of 

 this species — from Gorner Grat near Zermatt — which agrees in the main with that 

 of C. latifolium. — The flowers are protandrous, but the possibility of automatic 

 self-pollination remains. When expanded their diameter is about 15 mm.; the 

 white petals are streaked with dark veins converging to the base of the flower; 

 and nectar is secreted at the bases of the stamens. After anthesis the stamens 

 diverge but little, and their anthers dehisce successively, first those of the outer, 

 and then those of the inner ones. After the pollen is shed all the stamens curve 

 outwards. The five styles are closely apposed in the just-opened flower, and 

 are scarcely 2 mm. long ; they elongate, however, till at the time when the five 

 outer anthers have dehisced their length is about 5 mm. At this stage they diverge 

 somewhat, their stigmas being receptive, and remaining so till all the stamens have 

 shed their pollen. During anthesis, therefore, each flower passes through a male 

 stage, then becomes hermaphrodite, and finally enters on a female condition. 



