(1914) The Origin Of Some Garden Irises by Dykes

Gardeners' Chronicle p.48, July 16, 1914

NOTES ON IRISES.



THE ORIGIN OF SOME GARDEN IRISES.

About two years ago I was able, by the kindness of the Hon. N. C. Rothschild and of Dr. A. v. Degen, of Budapest, to see a dried specimen of an Iris which had. been discovered on the Velebit Range, in Dalmatia. This was recorded in a paper on the local vegetation by Dr. Degen* as being related rather to I. chamaeiris Bert and to the I. lutescens Lamarck than to I. variegata L. The branching stem and the wholly herbaceous spathes showed that it had nothing to do with the French I. Chamaeiris or lutescens, while the fact that the outer edges of the spathe valves were not keeled was sufficient evidence that the Iris was not merely a form of the Balkan I. Reichenbachii.

In April, 1913, I went to Dalmatia in search of Irises, and by the kindness of the late Herr Dobiasch, of Zengg, in Croatia, was provided with a native guide to take me to the exact spot on the Velebit Range where this Iris was known to grow. The mountains rise very abruptly from the sea coast and consist of very rough and almost barren limestone. In former days, when this coast was subject to Venice, tribute appears to have been paid in timber, with the result that the hills were almost entirely denuded of trees, and it is only recently that, further north in the neighbourhood of Fiume, attempts have Been made towards reafforestation on any large scale.

The Iris, of which I was in search, grows in a shallow cup-shaped hollow near the summit, at a height of some 4,000 feet. Just before we reached the edge of the cup, and while we were still on the south-western slope facing the Adriatic, I found growing among the limestone rocks a few Iris leaves, together with Crocuses and Muscari. My guide urged that it was hardly worth while to stop to collect any of these plants because we had almost reached our destination, where it was far more abundant. However, I took up a few plants, and then we soon reached the top. In this depression patches of snow were still lying on the north side of rocks, and all around were Gentiana tergestina, a near relative if not a form of G. verna ; Crocuses, of a species as yet undetermined; a yellow-flowered Primula; and, coming up among them all, the young leaves of an Iris, obviously belonging to the bearded section. The soil of the hollow was a layer of black vegetable mould overlying the limestone below.

During the present year the plants which I brought away with me have flowered well. It was interesting to watch them develop as they grew side by side. The foliage of the plants from the south-west face was noticeably glaucous and the entirely scarious spathes pointed to I. pallida. When the flowers opened it was obvious that here was one more of the long series of plants which in the north, near Roveredo, are called I. Cengialtii and in the south I. illyrica.

The plants from the hollow at the top had much greener foliage and were evidently of two kinds, for the spathes were in one case wholly green and in the other scarious in the upper part and green at the base. In both cases, the stems branched and the slightly-ribbed foliage of the plants with wholly green spathes led me to conclude that Dr. Degen's Iris must be a form of I. variegata L., which is common in many parts Of Hungary.e This was what they eventually proved to be. The standards are of a clear, pale yellow and the red-purple veining on the falls is not heavy, and I have no doubt that the veins had wholly disappeared, in the drying of the original herbarium specimens. The behaviour of Iris flowers as they dry is very erratic. Some keep their colours to an astonishing degree, while others, the yellows especially, rapidly lose all traces of their original hue and become merely a light brown.

It was sufficiently surprising to find I. pallida and I. variegata growing together, but a still greater surprise was the third variety of Iris, which had partly scarious and partly green spathes. The four-flowered inflorescence was that of a small I. germanica, and only the slightly brownish tinge of purple in the buds showed that there was any difference. When the flowers eventually unfolded they were at once interesting and disappointing. They were interesting from the fact that they were evidence that the so-called squalens and sambucina are, as I had long supposed, hybrids of I. pallida and I. variegata; and disappointing because they proved to be only an Iris which we have long had in our garden?, but which is no great ornament to them.

In the standards the yellow and the purple of the two parents fight for the mastery, and produce that dingy shade of dull purple which fully justifies the name of squalens. The falls are of a pale reddish-purple with thick darker veins, which allow the whitish ground to show between them only near the end of the beard. This is composed of whitish hairs tipped with yellow, and the flowers are, in fact, a typical I. squalens.

All the plants I have described are naturally small, growing as they do in poor soil at a considerable elevation, but I have no doubt that they will develop under better conditions to more than the 15 or 18 inches to which they have attained in this dry year in poor, stony soil.

The discovery of these three plants, the squalens hybrid and its two parents, pallida and variegata, growing together in a locality which certainly was never inhabited, and where they could scarcely have been planted by the hand of man, goes far to explain the origin of many of our garden bearded Irises. I have a whole series of hybrid forms, coming chiefly from the neighbourhood of Bozen and Riva, in the Southern Tyrol, in some of which the yellow of variegata predominates, while in others the purple of the pallida is more apparent. Judging from the localities from which they come, I never felt confident that they might be described as natural hybrids between I. pallida and I. variegata, but after my experience in Dalmatia I am inclined to think that it is extremely probable that they are really wild plants.

Typical I. variegata, such as we know it from Hungary and the Balkans, is not now known to grow at Bozen ; but, at any rate, there grows near that place a plant which closely resembles I. variegata, though certain characteristics and the fact that it does not readily set seeds incline me to think that it is a hybrid and not merely a form of that species. In the same neighbourhood forms of I. pallida are also abundant, and I have now little doubt that the original parents of the many so-called " Gennan " Irises of our gardens are to be sought among these plants.

Whether the problem of the origin of Iris germanica itself will ever be solved is doubtful, but I am almost inclined to suggest that it may be of hybrid origin. This would explain many of the difficulties, its almost complete sterility, the frequent malformation of the flowers, and the fact that it has never been found wild. The chief difficulty that is not explained lies in I. germanica's habit of beginning to grow in autumn instead of waiting for spring. If it were not for this there would seem to be no reason why I. germanica should not have resulted from a cross between I. aphylla and I. pallida. The flowers of the latter especially are so variable in their shades of colour that the many varying colour forms of I. germanica could easily be produced and the wholly herbaceous, often purple-flushed spathes of I. aphylla would combine with the wholly scarious spathes of I. pallida to give us the partly scarious and partly herbaceous, often purple-flushed spathes of I. germanica.

These suggestions are only put forward tentatively, but it would be interesting to know whether any seedlings have already been obtained by crossing I. aphylla and I. pallida, or any other tall, bearded Irises. I have made the cross recently and hope to obtain seeds which may throw more light on the vexed question of the origin of our garden bearded Irises. W.R. Dykes, Charterhouse, Godalming

For more information on historic Irises visit the Historic Iris Preservation Society at

-- BobPries - 2014-07-10