Excerpt: ...whilst 39 flowers fertilised illegitimately did not yield a single capsule or seed. Therefore the fertility of the six legitimate to that ...
Show synopsis
Excerpt: ...whilst 39 flowers fertilised illegitimately did not yield a single capsule or seed. Therefore the fertility of the six legitimate to that of the several illegitimate unions, as judged both by the proportion of flowers which yielded capsules and by the average number of contained seeds, is as 100 to 0. Oxalis speciosa. This species, which bears pink flowers, was introduced from the Cape of Good Hope. A sketch of the reproductive organs of the three forms (Figure 4.11) has already been given. The stigma of the long-styled form (with the papillae on its surface included) is twice as large as that of the short-styled, and that of the mid-styled intermediate in size. The pollen-grains from the stamens in the three forms are in their longer diameters as follows: - Table 4.c. Oxalis speciosa. Diameters of pollen-grains in divisions of the micrometer. Column 1: Source of Pollen-grains. Column 2: Minimum diameter. Column 3: Maximum diameter. From the: Longest stamens of short-styled form: 15 to 16. Mid-length stamens of short-styled form: 12 to 13. Longest stamens of mid-styled form: 16. Shortest stamens of mid-styled form: 11 to 12. Mid-length stamens of long-styled form: 14. Shortest stamens of long-styled form: 12. Therefore the extreme difference in diameter is as 16 to 11, or as 100 to 69; but as the measurements were taken at different times, they are probably only approximately accurate. The results of my experiments in fertilising the three forms are given in Table 4.29. Table 4.29. Oxalis speciosa. Column 1: Nature of the Union. Column 2: Number of Flowers fertilised. Column 3: Number of Capsules produced. Column 4: Average Number of Seeds per Capsule. Long-styled by pollen of longest stamens of short-styled. Legitimate union: 19: 15: 57.4. Long-styled by pollen of longest stamens of mid-styled. Legitimate union: 4: 3: 59.0. Long-styled by pollen of own-form mid-length stamens. Illegitimate union: 9: 2: 42.5. Long-styled by pollen of...
Hide synopsis