374 ANGIOSPERMAEDICOTYLEDONES 



other Arctic species (Nos. 860, 872, and 889-891) rapidly set fruits, and are otherwise 

 well adapted to the conditions of life obtaining in high latitudes. Warming describe 

 them as probably homogamous, and relying upon automatic self-pollination (cf. Loew 

 ' Blutenbiol. Floristik,' p. 99). 



889. P. fragiformis Willd., var. parviflora Trautw. (the species=P. emargi 

 nata Pursh, according to Abromeit, Bot. Ergeb. von Drygalski's Gronlandsexped., 

 p. 8). In Spitzbergen this species is one of the earliest spring plants, and wa< 

 observed in flower 21.6/96, 30. 6/82, 1.7/98, and 7.7/61. The last two dates appl} 

 to North-east Land in 8o N. lat. Andersson and Hesselman state that abundan 

 fruits are set (' Bidrag till Kanned. om Spetsbergens o. Beeren Eil. Karlvaxtfiora. 

 pp. 19-20). 



The specimens which Vanhoffen collected in Greenland and described as tht 

 variety (a) typica (=P. emarginata Pursh) bear flowers 15-17 mm. in diameter 

 with dark yellow petals traversed by darker veins. In the variety (c) elatior (=P 

 fragiformis Willd.) the flowers are larger, their diameter being not infrequentl) 

 20 mm. : petals pale yellow, but darker and distinctly veined at their bases. Th< 

 development of the petals is clearly dependent upon oecological conditions. 



Ekstam says that this species and its variety parviflora are also native t< 

 Nova Zemlia (Bot. Jahrb., Leipzig, xxii, 1897, p. 195). 



890. P. pulchella R. Br. This species was found flowering in Spitzberger 

 from June to the beginning of September, chiefly, however, in the second half 

 July. Fruits are set and ripened in a normal way (Andersson and Hesselman 

 'Bidrag till Kanned. om Spetsbergens o. Beeren EiL Karlvaxtfiora,' p. 19). Severn 

 varieties of this species occur in Greenland (Abromeit, 'Bot. Ergeb. von Drygalski: 

 Gronlandsexped.,' pp. 7-8). 



891. P.nivea L. This species was found flowering in Spitzbergen on 12.7/90 

 and ripe fruits were collected on 6.8/82 (Andersson and Hesselman, op. cit., p. 20) 

 It is very polymorphous in Greenland. Here the yellow petals project but little 

 beyond the calyx : numerous fruits were noticed (Abromeit, op. cit., pp. 9-1 1). 



Visitors. Lindman noticed a medium-sized fly on the Dovrefjeld. 



892. P. rupestris L. This species, which was studied at Bozen by Schub 

 (' Beitrage,' p. 68), is capable of automatic self-pollination, for the inner anther.- 

 incline somewhat towards the middle of the flower, so as to be above the simul 

 taneously mature stigmas upon which pollen can therefore fall. As but little nectai 

 is secreted, and the white flowers are not conspicuous, the number of insect-visit; 

 is small. 



Visitors. Schulz observed flies, beetles, and bees. MacLeod saw 5 Syrphide 

 and 5 Muscids (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, p. 431). Loew noticec 

 Apis, skg., in the Berlin Botanic Garden. 



893. P. alba L. The flower mechanism of this species agrees, according tc 

 Kirchner (' Flora v. Stuttgart,' p. 447), with those of P. verna, P. opaca, and P 

 Anserina. 



894. P. micrantha Ram. In the flowers of this species, according to Kerner 

 the stamens form a hollow cone which covers the nectar-secreting receptacle. 



