. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 98 AN GIOSPERMAE—DICOTYLEDONES. Fig. 259. Menyanthes trifoliaia, L. (after Warminfj). An isostylous flower from Julians- haab, in Greenland, in longitudinal section (X 3). average 26 yu, long and 50 /j, broad, while those of the short-styled form are 120 /a long and 63 ^ broad. In the short-styled flowers I have examined at Kiel the stigma is situated in the throat of the corolla, while in long-styled ones it projects several millimetres from this. The anthe
. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 98 AN GIOSPERMAE—DICOTYLEDONES. Fig. 259. Menyanthes trifoliaia, L. (after Warminfj). An isostylous flower from Julians- haab, in Greenland, in longitudinal section (X 3). average 26 yu, long and 50 /j, broad, while those of the short-styled form are 120 /a long and 63 ^ broad. In the short-styled flowers I have examined at Kiel the stigma is situated in the throat of the corolla, while in long-styled ones it projects several millimetres from this. The anthers diverge in a swallow-tailed fashion, and their height is of course inversely proportional to that of the stigma. Their pollen-covered surfaces are directed inwards. Heinsius describes the extremely long stigmatic papillae of the two forms as pretty much the same, but it seems to me that there is a difference in size approximately proportional to that of the two kinds of pollen-grain. He also states that though plants of the same kind are associated in groups, legitimate crossing is frequent as indicated by the size of the pollen-grains adhering to the stigmas. Kerner and Warnstorf say that the flowers are not only dimorphous, but also feebly pro- togynous. According to the former, automatic self-pollination can take place pseudo-cleisto- gamously in the closed flowers. Visitors.—Sprengel observed humble-bees, corresponding in size to the flowers. At Kiel I have only seen the beetle Meligethes, while Warnstorf only noticed small beetles and flies at Ruppin. Heinsius saw the butterfly Pieris rapae L., skg., in Holland. In Dumfriesshire Apis and a humble-bee have been recorded (Scott-Elliot, ' Flora of Dumfriesshire,' p. 119). 579. Limnanthemtun S. P. Gmel. Flowers dimorphous, with concealed nectar, secreted at five places between the roots of the filaments. 1889. L. nymphoides Hoffmgg. et Link (= Menyanthes nymphoides Z., and Villarsia nymphoides 7ot/.). (Kuhn, Bot. Ztg.,
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