TABLE 5.31. Primula Sinensis. Preponderance of long-styled over the short-styled form.
Column 1: Name of owner or place. Column 2: Long-styled form. Column 3: Short-styled form. Column 4: equal-styled variety.
Mr. Horwood : 0 : 0 : 17. Mr. Duck : 20 : 0 : 9. Baston : 30 : 18 : 15. Chichester : 12 : 9 : 2. Holwood : 42 : 12 : 0. High Elms : 16 : 0 : 0. Westerham : 1 : 5 : 0. My own plants from purchased seeds : 13 : 7 : 0. Total : 134 : 51 : 43.
In a state of nature the long and short-styled forms would no doubt occur in nearly equal numbers, as I infer from the analogy of the other heterostyled species of Primula, and from having raised the two forms of the present species in exactly the same number from flowers which had been LEGITIMATELY crossed. The preponderance in Table 5.31 of the long-styled form over the short-styled (in the proportion of 134 to 51) results from gardeners generally collecting seed from self-fertilised flowers; and the long-styled flowers produce spontaneously much more seed (as shown in the first chapter) than the short-styled, owing to the anthers of the long-styled form being placed low down in the corolla, so that, when the flowers fall off, the anthers are dragged over the stigma; and we now also know that long-styled plants, when self-fertilised, very generally reproduce long-styled offspring. From the consideration of this table, it occurred to me in the year 1862, that almost all the plants of the Chinese primrose cultivated in England would sooner or later become long-styled or equal-styled; and now, at the close of 1876, I have had five small collections of plants examined, and almost all consisted of long-styled, with some more or less well-characterised equal-styled plants, but with not one short-styled.
With respect to the equal-styled plants in the table, Mr. Horwood raised from purchased seeds four plants, which he remembered were certainly not long-styled, but either short or equal-styled, probably the latter. These four plants were kept separate and allowed to fertilise themselves; from their seed the seventeen plants in the table were raised, all of which proved equal-styled. The stamens stood low down in the corolla as in the long-styled form; and the stigmas, which were globular and smooth, were either completely surrounded by the anthers, or stood close above them. My son William made drawings for me, by the aid of the camera, of the pollen of one of the above equal-styled plants; and, in accordance with the position of the stamens, the grains resembled in their small size those of the long-styled form. He also examined pollen from two equal- styled plants at Southampton; and in both of them the grains differed extremely in size in the same anthers, a large number being small and shrivelled, whilst many were fully as large as those of the short-styled form and rather more globular. It is probable that the large size of these grains was due, not to their having assumed the character of the short-styled form, but to monstrosity; for Max Wichura has observed pollen-grains of monstrous size in certain hybrids. The vast number of the small shrivelled grains in the above two cases explains the fact that, though equal-styled plants are generally fertile in a high degree, yet some of them yield few seeds. I may add that my son compared, in 1875, the grains from two white-flowered plants, in both of which the pistil projected above the anthers, but neither were properly long-styled or equal- styled; and in the one in which the stigma projected most, the grains were in diameter to those in the other plant, in which the stigma projected less, as 100 to 88; whereas the difference between the grains from perfectly characterised long-styled and short-styled plants is as 100 to 57. So that these two plants were in an intermediate condition. To return to the 17 plants in the first line of Table 5.31: from the relative position of their stigmas and anthers, they could hardly fail to fertilise themselves; and accordingly four of them spontaneously yielded no less than 180 capsules; of these Mr.