. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. Fig. jyi. Irii Picudacorus,, L. (1-3. after Hcrm. Muller, 4. from nature). (i) Transverse section through the perianth tube. 12) Do., through the perianth, at the point where the sepals and petals become free. (3) Transverse section somewhat higher than (2), showing the boundaries of the nectar-passages, a, style; a'a' a', petaloid stylar branches; ^, nectar-passages; c, adherent part of filament; ddd^ sepals; rf'rf'rf', petals; ece, ridges on sepals. (4) Fl
. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. Fig. jyi. Irii Picudacorus,, L. (1-3. after Hcrm. Muller, 4. from nature). (i) Transverse section through the perianth tube. 12) Do., through the perianth, at the point where the sepals and petals become free. (3) Transverse section somewhat higher than (2), showing the boundaries of the nectar-passages, a, style; a'a' a', petaloid stylar branches; ^, nectar-passages; c, adherent part of filament; ddd^ sepals; rf'rf'rf', petals; ece, ridges on sepals. (4) Flower from the side (X 2): one of the three petaloid stylar branches is lifted up to show an anther (a) and a stigma (i); p, sepal with ; /, petal. the flower, where nectar is secreted by the base of the perianth, and stored in the tube between this and the style. The only means of access is found between the three large sepals, which serve as platforms, and the three petaloid stylar branches situated above them. Each of these three entrances is divided into two separate tubes by the fila- ments, which are fused with the sepals. Visitors seeking nectar creep forward on the platform under the stylar branch, bending back the upper side of the litde stigmatic lappet in doing so, and dusting it with the pollen brought from another flower. In creeping further, the insect brushes against the anthers, which have dehisced down- wards by two longitudinal slits, and dusts its back with fresh pollen. After having extracted nectar it creeps out backwards, but is unable to brush against the upper side of the stigmatic lobe again, as it has once more sprung upwards. Cross-pollina- tion therefore takes place regularly, and occasionally also self-pollination as an exception; the latter, however, cannot occur automatically. A proboscis 7 mm. long is necessary to reach the nectar, and 15 mm. long to suck it all out. The flowers occur in three oecological forms:— (a) bomhophila Knuth
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisheroxfor, bookyear1906
