. Handbook of flower pollination : based upon Hermann MuÌller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 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
. Handbook of flower pollination : based upon Hermann MuÌller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 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, â 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 Fig. 2^3. Pyrola uiiiflora,
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