ERICACEAE 



53 



stigma, upon which are damp glistening spots (considered as nectar by Ricca), that 

 visitors lick, at the same time depositing any pollen adhering to their proboscis. 

 Finding no nectar they climb up the style, attracted by the orange-yellow horns 

 of the anthers, and busy themselves with the pollen, so that the proboscis is again 

 dusted. Crossing is therefore easily effected by insects, but Hermann Miiller says 

 that the projecting position of the stigma usually prevents automatic self-pollination. 

 Kerner gives a different account. He says that at first the peduncle is bent in such 

 a way that the style projects vertically downwards, while the anther-pores face 

 upwards, autogamy being therefore impossible. Insect visitors first touch the stigma, 

 and then tip over the anthers, which sprinkle them with pollen. Later on the 

 peduncle becomes less bent, so that the flower is brought into a nodding position, 

 ■while the style is directed obliquely downwards and the stigma now lies directly 

 below the anthers. At 

 the same time the fila- 

 ments have bent round, 

 so that the anther-pores 

 face downwards, and pol- 

 len can easily fall from 

 them upon the stigma, 

 auiomaticallyeffecting self- 

 pollination. 



Warming says that 

 in plants growing in 

 Greenland the distance 

 between the stigma and 

 anthers is less than in 

 P. rotundifolia, so that 

 automatic self-pollination 

 is more easily effected. 

 (Cy Fig. 233.) According 

 to Lindman, the flowers 

 on the Dovrefjeld have a 



smaller diameter (13 mm.) than those of the Alps. Ekstam says that the diameter 

 varies from 12 to 20 mm. in the Swedish Highlands, while that of the faintly odorous 

 flowers of Nova Zemlia is 10-20 mm. The mechanism in the latter locality agrees 

 with the description given by Warming, and sometimes suggests that of P. rotundifolia. 

 No nectar is secreted. 



Fig. 2^3. Pyrola uiiiflora, jL. (after E. Wanning). A. Flower seen 

 from tlie side. B. Do. from tiie front (x 2). C. Flower-bud sheltered 



by a bract. D,E,F. Stamens of an older flower (x 8). G. Stigma 



seen from above. N, I. Stamens of a bud, before they have turned round 

 (X S). A'. Flower of />. rotundijolia, L. (x 2). 



533. Hypopitys Dill. 



Homogamous flowers with concealed nectar, secreted, according to Kerner, by 

 the fleshy base of the corolla. 



1787. H. multiflora Scop. (=Monotropa hypopitys Z.). (Kirchner, ' Flora v. 

 Stuttgart,' p. 530; Warnstorf, Verb. bot. Ver., Berlin, xxxvii, 1896.) — The flowers of 

 this species, which like the whole of the plant are pale-yellow in colour, are homo- 

 gamous and arranged in racemes. The terminal one is pentamerous, and the lateral 



