(1917) Variation In Form Of Iris by A.J. Bliss
Gardeners' Chronicle p.1, July 7, 1917
VARIATION OF FORM IN IRIS.
IN an article on teratology in Iris flowers by Miss Armitage (Gard. Chron., Oct. 28, 1916), the conclusion is reached that abnormalities are the outcome of a sporting tendency, finding expression in particular individuals. Among crossbred seedlings abnormal flowers often appear, those noted in the article being the most common, and my experience confirms this conclusion. The tendency to sport indefinitely or to produce malformations is characteristic of certain varieties, such as Queen of May and Gracchus, and is inherited to a greater or less extent in their seedlings, but it is not invariable, some individuals or some crosses giving perfectly normal flowers.
Of the abnormalities noted, the two most interesting from the florist's point of view are the tetramerous flowers and those with six equal and similar segments.
With regard to the former, nutrition seems to have some influence. In many varieties and seedlings, especially of the Pallida type, the first flowers at the top of the spike on all the strongest stems are tetramerous, the succeeding flowers and those on weaker stems being all normal, with an occasional exception. Intrinsically, these tetramerous flowers, when perfectly regular, as they usually are, are often as beautiful and graceful as the normal trimerous flowers. In the border they simply appear as
large and fine flowers, and few notice the departure from the normal form until it is pointed out, but it is, perhaps, psychologically interesting that when it is realized disapproval is generally expressed.
The " Clematis "-flowered Iris, with six segments alike, is more interesting, and, though in appearance it departs even more from the typical form, seems to me to be beautiful in its own way if it is quite regular and uniform both in form and colouring, and if all the flowers of the variety are of this type. But even when this is practically the case, flowers will always be found in which the modification is incomplete, and occasionally even quite normal flowers will occur, from which it appears that it is not a true varietal or Mendelian unit character, but rather a phenomenon of the same nature as peloria, as I have suggested in the case of the florist's Gladiolus. It is interesting to compare it with the florist's Gladiolus, and to observe in the Iris also how the changes in form, colour and markings are linked together with reference to their function. As in the Gladiolus, it is the inner segments or standards which are modified, being transformed into falls, assuming the same position, either spreading or hanging, and with the colour and markings characteristic of the variety, and also developing a beard. The change then may be considered, apart from aesthetic considerations, as a progressive one, and even more so than in the Gladiolus, since the falls are more highly specialized than the standards, and whereas in the Gladiolus there is a less of colour markings, in the Iris there is, besides the production of a beard, an assumption, or, at any rate, an increase in intensity of colour and markings, either absent or less developed in the standards.
It might also be useful to compare closely and critically the phenomena of doubling and peloria. I venture to suggest only one broad general contrast. The most common form of doubling consists in the conversion of the stamens, and even sometimes of the pistils, into petals, and may, therefore, be looked upon as a centripetal tendency. On the other hand, peloria very often consists either in a transformation of the inner whorls of segments to the form and colour of the outer segments, or to an increase in number of these outer segments, and so appears to consist of centrifugal tendency in
Besides the malformations noted in the article, another may be mentioned of a somewhat different nature, but which appears to be more definite, and to be inherited as a distinct unit character. In Iris plicata Mme Chéreau, and in several other Plicata varieties, the falls are cockled at the tips, and the blade is lopsided or bilaterally unequal. All the flowers are affected, though in varying degree, and only very occasionally can a flower be found with perfect or nearly perfect falls. This malformation, or one more or less similar, also occurs, but, in my experience, more rarely, in varieties and seedlings of other sections of bearded Irises, and seems to be especially associated with the Plicata type. Among seedlings from Mme Chéreau many will have similar malformed falls, in some cases so accentuated that the whole blade is contorted and crunipled up and partly aborted, but only in those which also display the Plicata type of form and colour. Non-plicata seedlings from the same cross and the same pod of seed have normal flowers, with no cockling of the tips of the falls, though occasionally there is some creasing or crumpling of the petals, and the blade is often still lopsided. Although this malformation is exhibited in so slight a degree in the best and newest Plicata varieties, that from a garden point of view it is negligible, it is always present when the form of the flowers is of the Pallida type, and the only Plicata (colour type) that I have seen entirely free from it is one which has flowers of the Variegata or Neglecta type that is, with oval instead of cuneate falls.
The lopsidedness of the blade of the falls may be connected with this cockling of the tips, but it is a much more general malformation; few, if any, bearded Irises of the Pallida type are free from it. It is, in fact, so general that perhaps it may be due to the development of the flower, and the folding of the segments in the bud, as the deficient half of the blade is always to the right. This imperfection in the individual flower is noticed by few, and, perhaps, does not detract from the general effect in the border, but it is an eyesore to the florist. The fact is that the race of bearded Irises is in the making, and at present, for all their general beauty, there are none among the standard varieties that does not show some imperfection or other. Among the newer varieties there are some now, such as Monsignor and Ed. Michel, and some of Sir M. Foster's later seedlings, that are approaching an ideal standard of form and colour. But what is needed is the patient and -single-minded work of men such as those who have given us the Auricula and Dahlia, Chrysanthemum and Rose, to perfect the individual flower, and we may hope that among those who come back from the war there will be many to whom such work will appeal.---- A. J. Bliss.
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