THE ORIGIN OF THE HYBRID PRIMULA ELATIOR×VULGARIS DEMONSTRATED EXPERIMENTALLY IN THE FIELD, WITH NOTES ON OTHER BRITISH PRIMULA HYBRIDS

Abstract

S elatior in Britain1," I had the pleasure of showing to Dr Bateson, Miss E. R. Saunders, and others the various Primula hybrids I had described therein-namely : (I) P. elatior x vulgaris, ( 2 ) P. elatior x veris, and (3) P. veris x vulgaris-all growing in a wild state in certain woods in Essex, Suffolk, and Cambridgeshire.On this occasion Dr Bateson (without disputing my assumption that the plants in question really were hybrids) pointed out that, for purposes of absolute scientific accuracy, their hybrid origin, even if practically certain inferentially, ought to be demonstrated incontestibly by means of definite experiment.Thereupon it was decided to attempt to accomplish this by planting some Oxlips (P. elatior) in woods wherein Primroses (P. vulgaris) only were growing and some Primroses in other woods wherein Oxlips only were growing, and then waiting to see whether plants similar to those I had described as hybrids between these two species would appear naturally in the course of time.That the plants I had described as hybrids were really such might, of course, have been demonstrated much more easily and quickly by artificially pollinating flowers of either of the two reputed parents with pollen from flowers of the other on covered plants growing in cultivation and then raising plants from any fertile seed resulting. As a matter of fact, Miss Saunders succeeded in doing this soon after the time when our experiments described herein were begun2, and since then Mr E. G. Highfield has done the * Miss Saunders writes me: '' In 1899 and rgoo.1 raised a number of hybrids between P. elatior and P. vulgaris from crosses which I made for the purpose of testing the views expressed in your original paper. The results entirely confirmed your conclusions; but, having done this and having found the sterility so great that there was no likelihood of obtaining any genuine ratios in support of the Mendelian Theory or otherwise, I did not continue the experiments and no record was published." Journ. Linn.

Biological Flora of the British Isles: Primula vulgaris Huds. (P. acaulis (L.) Hill)

“…Whale (1982), on the other hand, noted that in many situations populations of P. vulgaris and P. elatior are not contiguous, suggesting that there is little evidence of competition between the species in any direct sense. This is supported by transplant experiments of Christy (1922b), who in 1898 planted nine separate patches of P. vulgaris in a pure P. elatior wood, some of which were still extant in 1915.…”

“…The hybrid is fertile and hybrid swarms arise (Géhu & Géhu‐Franck 1957). Although it is believed that internal restricting factors such as seed incompatibility are more important than external differences in habitat preferences, Christy (1922b) reported that 17 years after transplanting P. elatior in a Primrose wood, and Primroses in a P. elatior wood to observe natural hybridization, hybrids were found in the oxlip wood into which Primroses had been transplanted, but that no hybrids were observed in the Primrose wood. Studies of a long‐established hybrid swarm in Buff Wood, Cambridgeshire, showed that individuals of P. vulgaris were distinct, but there was no discontinuity between the hybrid and P. elatior , and some plants with the morphology of oxlip were actually of hybrid origin (Gurney et al .…”

Studies in British Primulas

“…The introduction of one of the species into a wood in which only the other species occurred would thus be an experiment of great interest. Such an experiment has been performed; Christy (19226), in 1898, planted nine separate patches of Primroses in a pure Oxlip wood, Peverell's Wood in Essex; in 1915, it was found that more than one of the patches of Primroses still survived, and some interspecific hybrids had also been formed. It does not appear from Christy's account that the Primroses had spread to any extent; in fact, they seem to have decreased in number.…”