Note 8 — ON THE UTILITY TO FLOWERS OF THEIR BEAUTY.

As Mr. Darwin points out in the passage I have cited, and still more at large in his work "On the Different Forms of Flowers," a large proportion of existing plants are fertilized by the action of the wind; and again, many plants bear two kinds of flowers, the one conspicuous and attractive to insects, the other inconspicuous and which never open to admit the activity either of insects or of the wind. Moreover, there are various other agencies called into play. Some plants, such as the Hypericum perforatum, one of the commonest of the St. John's Worts, and probably the bindweed, are, it seems, fertilized by the withering of the corolla, which naturally brings the stamens into contact with the style, and so transfers the pollen grains from the one to the other.8 Other plants, again, such as the common centaury (Erythræa centaurium) and the Chlora perfoliata, are fertilized by the closing of the corolla over the anthers and stigma, not in the death but in the sleep of the plant.9 In the brilliant autumnal Colchicum, and in the Sternbergia, again, according to Dr. Kerner, Nature has recourse to a more complex machinery: the corolla first closes over the anthers, which are at a lower level than the stigma, and takes off some of the pollen; a growth of the corolla carries the pollen dust to the level of the stigma, and a second closing of the corolla transfers the pollen to the stigmatic surface. The pollen has been made to ascend to its proper place by an arrangement which reminds one of the man-engine of a Cornish mine.10 A similar arrangement is described as occurring in the bright-flowered Pedicularis.11