. Scientific lectures. Science; Natural history; Archaeology. i.] MODES OF CHECKING SELF-FERTILIZATION. 15 sequently incapable of fertilizing itself. In E. parvi- fiorum, on the contrary, the stamens and pistil come to maturity at the same Fig. 13.—Epilobium angustifolium. Fig. 14.—Epilobium parviflorum. , Let us take another case—that of certain Geraniums. In G. pratense all the stamens open, shed their pollen, and wither away before the pistil comes to maturity. The flower cannot therefore fertilize itself, and depends entirely on the visits of insects for the transference of the poll
. Scientific lectures. Science; Natural history; Archaeology. i.] MODES OF CHECKING SELF-FERTILIZATION. 15 sequently incapable of fertilizing itself. In E. parvi- fiorum, on the contrary, the stamens and pistil come to maturity at the same Fig. 13.—Epilobium angustifolium. Fig. 14.—Epilobium parviflorum. , Let us take another case—that of certain Geraniums. In G. pratense all the stamens open, shed their pollen, and wither away before the pistil comes to maturity. The flower cannot therefore fertilize itself, and depends entirely on the visits of insects for the transference of the pollen. In G. pyrenaicum, where the flower is not quite so large, all the stamens ripen before the stigma, 'but the interval is shorter, and the stigma is mature before all the anthers have shed their pollen. It is therefore not absolutely dependent on insects. In G. molle, which has a still smaller flower, five of the stamens come to ma- turity before the stigma, but the last five ripen simul- taneously with it. Lastly, in G. pusillum, which is least of all, the stigma ripens even before the stamens. Thus, then, we have a series more or less dependent on insects, from G. pratense to which they are necessary, to G. pusil- lum, which is quite independent of them ; while the size of the corolla increases with the dependence on Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lubbock, John, Sir, 1834-1913. London, New York, Macmillan and Co.
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