Journal of the Royal Horticultural Society, 3: 105-107 (1872)

XI. On imperfect Hybridity.
Isaac Anderson-Henry, Esq.

Among the same batch of seedlings from which I obtained Veronica Andersonii,V. salicifolia (syn. V. Lindleyana) + V. speciosa,—came one which, to all appearance, was a reproduction of the male parent pure and simple. And deeming it nothing else, I presented it to a friend, V. speciosa being then comparatively a new plant; and he, when he flowered it, came to tell me that it had come a very different thing in bloom to the true V. speciosa, having much longer flower-spikes and of a much lighter colour than those in that species, being of a light crimson instead of a dark purple, as in the V. speciosa.

A plant of this hybrid has since afforded a further illustration of a somewhat similar result.

Having obtained a suffruticose species of Veronica, under the name of V. Daubeneyiana, with light-coloured flowers striated with pink lines, in the way of V. fruticulosa, I crossed it on the last-mentioned hybrid, which became the seed-bearer. From this cross I succeeded in raising only two plants; and one of these I believe I have lost. But they seemed both alike in foliage and habit; but both so like the hybrid seed-bearers that I felt doubtful whether the cross had taken. I cannot speak with confidence as to their being identically alike, but only of their general aspect. The plant I still possess flowered for the first time this past season; and the singularity of its bloom drew my attention to it more particularly than before. It had, like the seed-bearer, thick fleshy pyriform leaves, but somewhat smaller and more closely set on the stem; but instead of being, like it, simply cruciform, they were obliquely decussate, therein slightly approaching the male parent, a creeping alpine species whose prostrate stems show still more the same deflected arrangement of the leaves. It was only on a close examination of the part, however, that any resemblance to the male, V. Dauheneyiana, could be observed. In fact I looked upon it as another of the many failures I had had in my attempts to effect the inverse cross on it. When it at last bloomed, my hopes of having effected a partial cross, if I may use such a term, were strengthened. Like V. Daubeneyiana, which has a spikelet with a few blooms, it came even short of it, having had only two flowers, and these much lighter in colour, and no nearer to the male than the hybrid female parent; but whether this is its true permanent character I dare not assert, as it bore no more than this one spikelet of two flowers.

In the first of the above instances the hybrid seemed, till it flowered, a repetition of the male parent; in the second, it seemed, till it bloomed, a repetition of the female parent, with such slight differences in the arrangement and slightly smaller size of the foliage as might occur in a purely normal seedling. In fact, seldom have I ever seen two hybrids with so much of one parent and so little of the other.

I have no doubt something of the same kind occurs among Rhododendrons. But I may only instance one case where I crossed R. Edgworthii on R. caucasicum; the seedlings, ever few when the cross is a severe one (by which term I mean such instances as where the species do not affect each other kindly), were only two in number; and though now about ten years old they show no indications of setting for flower. But while they have both the glabrous foliage of the seed-bearer, and even the ochreous tint underneath, they differ in having pyriform instead of its lanceolate leaves. But though in these particulars they depart from the normal state of R. caucasicum, they have not one feature of R. Edgworthii, the male parent. The other case is where I crossed the same R. Edgworthii on R. Jenkinsii. Here the seedlings, again only two in number, were all of the mother, except in having again the pyriform foliage, in which, be it observed, it is a departure from both parents, both having lanceolate leaves, those of R. Jenkinsii being acutely so. The hybrid in this latter case is budded for flower; but the flowers of both parents are white, and both sweet-scented, and among the largest of the genus, though the scent, texture, and forms of the flowers are different; so that I look for surer tests in the coming flowers, though these may be more perplexing too than any that yet appears. It is proper to observe that I take the utmost precaution in all my crossing-operations to prevent miscarriage in any possible way.

While treating of my difficulties with this R. Edgworthii, one of the most peculiarly constituted, as it is one of the most peculiarly featured of all the Rhododendron tribe, having its rugose leaves densely pubescent on the upper while it is perfectly shaggy with tomentum on the under side, every stem being clothed with the same tomentum, I have another most singular peculiarity to note in regard to it, namely that while it will cross other species it will take on a cross from none,—that is to say, while it has been repeatedly made the male, it has never with me, though I have tried it often, nor with any other that I have heard of, submitted to become the female parent. I have crossed it repeatedly on R. ciliatum, one of the minor forms, too, of Dr. Hooker's Himalayian species. It has been crossed, too, on R. formosum in this neighbourhood, I believe, in the Stanwell Nursery: but I never could get it to take on any cross whatever. R. Nuttalli behaved, with me, in the same manner; it would cross but not be crossed; but I did not persevere with it as I did with R. Edgworthii. Now I do not assert absolutely that R. Edgworthii, in the numerous tribe of which it is a member, may not be hybridized with some other of its kindred, but I could never get it to reciprocate a cross. And this remarkable circumstance of non-reciprocity has perplexed and defied me in innumerable instances throughout my long experience in these pursuits. It occurred to me that the pollen of larger forms might be of larger grains, and so might not pass through the necessarily small ducts of the styles of smaller species; yet R. ciliatum, a tiny species of 1 foot high, was crossed freely by R. Edgworthii, as I have just noticed, a species of 6 feet high. I even crossed this latter species on a pure Indian Azalea, though, by pulling the seed-pod before it was ripe, I raised no seeds of this latter cross.

In these hasty observations I merely wish to direct attention to such instances of imperfect hybridity in certain species, and the non-reciprocity in others, as I have noticed, in the hope of perhaps drawing out from others their experiences in such matters, which I humbly think are not unworthy the consideration of the Scientific Committee.

Anderson-Henry Bibliography