. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 60 THE BTRUCT0BE Of FLOWEKS. walls whlcli touch.; so that when they are fully grown the cohesion is firmly secured. An imitative cohesion is seen in the anthers of the Heartsease, which arises from the interlocking of marginal hairs down the sides of the cells. Anthers, when thas closely approximate without actual cohesion, are usually called " connivent," as in Ericaeece, and the word is perhaps appropriate to those of Solanum Dulcamara; but in this plant the union is very close, and mig
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 60 THE BTRUCT0BE Of FLOWEKS. walls whlcli touch.; so that when they are fully grown the cohesion is firmly secured. An imitative cohesion is seen in the anthers of the Heartsease, which arises from the interlocking of marginal hairs down the sides of the cells. Anthers, when thas closely approximate without actual cohesion, are usually called " connivent," as in Ericaeece, and the word is perhaps appropriate to those of Solanum Dulcamara; but in this plant the union is very close, and might even be considered as syngenesious. The rationale of the close approximation of anthers, or of actual cohesion between them, is the effect of insect agency, just as for the filaments; but the method of extraction of the pollen varies. In Viola, the proboscis is thrust through a small orifice between the connectival appendages of the lower pair of stamens, in order to reach the end of the honey-collecting spur. In Heaths and some of their allies, the anther-cells are at first in contact, and so prevent the pollen from escaping; but each anther is provided with two auricles which extend to the corolla. A bee on entering first strikes the projecting stigma, but its proboscis soon turns one of the auricles aside, which, acting as a lever, dislocates the rest, and a shower of pollen falls out. In Gompositce and Lobelia there is a trne piston action. The style continuing to elongate drives the pollen out of the cylinder formed by the anthers, and elevates it above the flower, thereby rendering it easy to be dispersed by insects. This is well seen in Centaurea (Fig. 11) ; (o) represents the stamens with the anther-cells closed above by the connectival appendages. The arrow shows the direction of the insertion of the proboscis of a bee to reach the annular. Fig. 11 CejUaurea. Stamena of. Please note that these images are extracted from scanned page images that may have been digitall
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Keywords: ., bookcentury1800, bookdecad, booksubjectflowers, booksubjectplants
