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 own-form shortest stamens. Illegitimate union : 11 : 0 : 0.
Long-styled by pollen of shortest stamens of mid-styled. Illegitimate union : 4 : 0 : 0.
Long-styled by pollen of mid-length stamens of short-styled. Illegitimate union : 12 : 5 : 30.0.
Mid-styled by pollen of mid-length stamens of long-styled. Legitimate union : 3 : 3 : 63.6.
Mid-styled by pollen of mid-length stamens of short-styled. Legitimate union : 4 : 4 : 56.3.
Mid-styled by mixed pollen from both own-form longest and shortest stamens. Illegitimate union : 9 : 2 : 19.
Mid-styled by pollen of longest stamens of short-styled. Illegitimate union : 12 : 1 : 8.
Short-styled by pollen of shortest stamens of mid-styled. Legitimate union: 3 : 2 : 67.
Short-styled by pollen of shortest stamens of long-styled. Legitimate union: 3 : 3 : 54.3.
Short-styled by pollen of own-form longest stamens. Illegitimate union: 5 : 1 : 8.
Short-styled by pollen of own-form mid-length stamens. Illegitimate union : 3 : 0 : 0.
Short-styled by both pollens mixed together, of own-form longest and mid-length stamens. Illegitimate union: 13 : 0 : 0.
Short-styled by pollen of longest stamens of mid-styled. Illegitimate union : 7 : 0 : 0.
Short-styled by pollen of mid-length stamens of long-styled. Illegitimate union: 10 : 1 : 54.
We here see that thirty-six flowers on the three forms legitimately fertilised yielded 30 capsules, these containing on an average 58.36 seeds. Ninety-five flowers illegitimately fertilised yielded 12 capsules, containing on an average 28.58 seeds. Therefore the fertility of the six legitimate to that of the twelve illegitimate unions, as judged by the proportion of flowers which yielded capsules, is as 100 to 15, and judged by the average number of seeds per capsule as 100 to 49. This plant, in comparison with the two South American species previously described, produces many more seeds, and the illegitimately fertilised flowers are not quite so sterile.
Oxalis rosea.
Hildebrand possessed in a living state only the long-styled form of this trimorphic Chilian species. (4/14. 'Monatsber. der Akad. der Wiss. Berlin' 1866 page 372.) The pollen-grains from the two sets of anthers differ in diameter as 9 to 7.5, or as 100 to 83. He has further shown that there is an analogous difference between the grains from the two sets of anthers of the same flower in five other species of Oxalis, besides those already described.