no 



ANGIOSPERMAE—DICOTYLEDONES 



265. D. aurea M. Vahl. — Warming says that this species differs from the pre- 

 ceding in having the nectar more deeply concealed. The long claws of the petals 

 are closely apposed to form a tube, so that only insects with a long proboscis can 

 reach the nectar. In the homogamous flowers automatic self-pollination can only be 

 effected by the long stamens, while the short ones serve for cross-pollination. 



266. D. alpina L. — Lindman says that this species is homogamous — on the 

 Dovrefjeld — and capable of automatic self-pollination. 



According to Ekstam, the protogynous-homogamous flowers in Nova Zemlia 

 agree in structure with those of Scandinavia and Greenland. The same botanist has 

 observed plants in Spitzbergen bearing flowers and fruits during the height of 

 summer (' Bliitenbiol. Beob. a. Spitzbergen,' p. 20). The flowers were homogamous, 

 5-7 mm. in diameter, faintly fragrant, and with yellow petals. 



Visitors. — In Spitzbergen, Ekstam observed that the flowers were visited by 

 a number of small Diptera. 



267. D. crassifolia L. — Warming says that this species is homogamous and 

 autogamous in the Arctic regions. 



79. Kernera Med. 

 Small white homogamous flowers, with half-concealed nectar. Four nectaries. 



268. K. saxatilis Reichb. (=Cochlearia saxatilis Lam.). (Herm. Miiller, 

 ' Alpenblumen,' p. 147.) — The flowers are homogamous. There is a green fleshy 



nodule secreting nectar on 

 either side the base of each 

 short stamen. The petals are 

 at first small and erect, but 

 subsequendy expand. The 

 anthers of the four long 

 stamens are close to those of 

 the two short ones : all six 

 dehisce introrsely, and are so 

 placed that an insect sucking 

 nectar must touch them with 

 one side, and the stigma with 

 the other side, thus favouring 

 cross-pollination. In dull weather the flowers remain half closed, when automatic 

 self-pollination takes place. The pistil turns to purple-brown in the older flowers. 



Visitors.— Hermann Muller— in the Alps— observed chiefly flies— 5 Muscidae, 

 an Empid, and 3 Syrphidae— also several bees — Andrena, and beetles — Meligethes. 



Fig. 33. Kernera saxalilis, Reichb. (zSlsTiieTm.MuWeT). A. 

 Flower seen from above. B. Flower after removal of two petals : 

 seen from the side; k, short stamen. (X 7.) 



80. Cochlearia L. 



White, odorous, homogamous flowers, either with half-concealed nectar, or else 

 nectarless. 



269. C. Armoracia. (Herm. Muller, ' Weit. Beob.,' II, p. 198 ; Kirchner, ' Flora 

 v. Stuttgart; p. 305; Warnstorf, Verh.bot.Ver., Berlin, xxxviii, 1896; Kerner, 'Nat. 



