auricula, to the abnormal elongation of the stamens of the long-styled form. In accordance with this view, they yield less seed when crossed with the long-styled form than with the short- styled. But they differ in an anomalous manner from the equal-styled plants of P. auricula in being extremely sterile with their own pollen.
Primula elatior.
It was shown in the first chapter, on the authority of Herr Breitenbach, that equal-styled flowers are occasionally found on this species whilst growing in a state of nature; and this is the only instance of such an occurrence known to me, with the exception of some wild plants of the Oxlip--a hybrid between P. veris and vulgaris--which were equal-styled. Herr Breitenbach's case is remarkable in another way; for equal-styled flowers were found in two instances on plants which bore both long-styled and short-styled flowers. In every other instance these two forms and the equal-styled variety have been produced by distinct plants.]
Primula vulgaris, BRIT. FL.
VAR. acaulis OF LINN. AND P. acaulis OF JACQ.
VAR. RUBRA.
Mr. Scott states that this variety, which grew in the Botanic Garden in Edinburgh, was quite sterile when fertilised with pollen from the common primrose, as well as from a white variety of the same species, but that some of the plants, when artificially fertilised with their own pollen, yielded a moderate supply of seed. (5/10. 'Journal of the Proceedings of the Linnean Society' 8 1864 page 98.) He was so kind as to send me some of these self- fertilised seeds, from which I raised the plants immediately to be described. I may premise that the results of my experiments on the seedlings, made on a large scale, do not accord with those by Mr. Scott on the parent-plant.
First, in regard to the transmission of form and colour. The parent-plant was long-styled, and of a rich purple colour. From the self-fertilised seed 23 plants were raised; of these 18 were purple of different shades, with two of them a little streaked and freckled with yellow, thus showing a tendency to reversion; and 5 were yellow, but generally with a brighter orange centre than in the wild flower. All the plants were profuse flowerers. All were long-styled; but the pistil varied a good deal in length even on the same plant, being rather shorter, or considerably longer, than in the normal long-styled form; and the stigmas likewise varied in shape. It is, therefore, probable that an equal- styled variety of the primrose might be found on careful search; and I have received two accounts of plants apparently in this condition. The stamens always occupied their proper position low down in the corolla; and the pollen-grains were of the small size proper to the long-styled form, but were mingled with many minute and shrivelled grains. The yellow-flowered and the purple-flowered plants of this first generation were fertilised under a net with their own pollen, and the seed separately sown. From the former, 22 plants were raised, and all were yellow and long-styled. From the latter or the purple-flowered plants, 24 long-styled plants were raised, of which 17 were purple and 7 yellow. In this last case we have an instance of reversion in colour, without the possibility of any cross, to the grandparents or more distant progenitors of the plants in question. Altogether 23 plants in the first generation and 46 in the second generation were raised; and the whole of these 69 illegitimate plants were long-styled!
Eight purple-flowered and two yellow-flowered plants of the first illegitimate generation were fertilised in various ways with their own pollen and with that of the common primrose; and the seeds were separately counted, but as I could detect no difference in fertility between the purple and yellow varieties, the results are run together in Table 5.32.
TABLE 5.32. Primula vulgaris.
Column 1: Nature of plant experimented on, and kind of union. Column 2: Number of flowers fertilised. Column 3: Number of capsules produced. Column 4: Average Number of seeds per capsule. Column 5: Maximum Number of seeds in any one capsule. Column 6: Minimum Number of seeds in any one capsule.