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Iris (Greek name for the rainbow)

(the Greek name for the rainbow, used as a title of this plant since the time of Hippocrates). Including Evansia, Gynandriris, Hermodactylon, Oncocyclus, Xiphion, &c. ORD. Irideoe. A genus of about a hundred species of mostly hardy herbaceous plants with creeping or tuberous rootstocks, natives of Northern temperate regions. Flowers in sheaths; perianth six-cleft; segments in two rows; three outer ones reflexed, often bearded at the base; three inner ones erect, usually smaller than the others; perianth tube short; stamens three, inserted at the base of the outer row of the perianth; anthers innate; style with three petal-like divisions. Capsule leathery, trigonous, dehiscing loculicidally. Leaves chiefly radical, equitant, sword-shaped or linear.

The numerous species and varieties of Iris, now in cultivation, comprise a large and most interesting group of hardy plants, remarkable alike for their curiously-constructed and quaintly-marked flowers, and for the peculiar manner in which many beautiful colours are blended in them. A large proportion of the commoner species do not need more than ordinary attention to secure a profusion of flowers annually; but there are several which require special treatment, and can then rarely be induced to flower. These are, however, well deserving of special attention, on account of the beautiful markings and combination of colours the limited number of flowers they bear more particularly exhibit. There are two large and distinct sections into which the Iris is usually divided according to its habit of growth, and these are distinguished by the one having long bulb-like corms, and the other creeping fleshy root-stocks or rhizomes. For convenience, they may be termed the bulbous and rhizomatous sections, and a reference made to each separately, as the proper treatment varies some what considerably with several of the species. The flowering season of the Iris is principally spring and early summer; but, with an assortment of the numerous species and varieties in each section, it may be prolonged throughout almost the whole year. Height in the plants varies from 2in. or 3in. in some species, to 3ft. or 4ft. in others; and a great diversity of habit is also represented.

Propagation. The plants belonging to the bulbous section of Iris may be raised in quantities from seed if desired. It is produced by many in both sections, if allowed, and should be sown in sandy soil, so soon as ripe, preferably in pans or boxes, which may be placed in a cold frame. Fig. 323 shows the way in which the seed capsule bursts, when ripe, for discharging its contents. The seeds germinate the following spring, and bulbs, sufficiently large for flowering, may be expected after three years' growth. Quantities of offsets may also be utilised for propagating purposes; but care should be taken not to injure the old bulb in removing them, or allow it to be kept too long exposed to the air. The rhizomatous section may be propagated by division; or by layering, if roots are not readily emitted in the ordinary way. Cultivation. The bulbous section, or Xiphions, are principally represented in gardens by what are known as English and Spanish Iris. Both are of Spanish origin, and vary chiefly in the size of the bulbs and flowers, and in the more curious combination of colours, as exhibited in the flowers of the former. I. filifolia, I. Histrio, I. persica, and I. reticulata, are very beautiful, and early flowering species, also of this section. They all succeed best in a light, rich, sandy soil, and in a situation fully exposed to sun, yet protected, if possible, from easterly or other strong winds. Efficient drainage in autumn and winter are important conditions, and the bulbs should not be removed from the soil more than is really necessary. Bulbous Iris are most attractive when planted in masses.

Of the rhizomatous species there are large numbers, which may be grouped according as their cultivation requires. The bearded, more commonly called the German Irises, comprise a number of varieties, having large and very handsome flowers; and, as they are among the easiest to cultivate, they are largely grown. Their rhizomes are formed on the top of the ground, and should not be covered with soil, or they will be liable to rot in winter. Dwarf-growing species, like alata, aphylla, biflora, Chamoeiris and its varieties, pumila with its varieties, and rubro-marginata, should be provided with a sunny position on a rockery, and be planted in light, rich soil. flavescens, florentina, germanica, lutescens, sambucina, and squalens, are a few of the stronger-growing bearded Iris, that are not so particular regarding the soil or situation wherein they are planted.

The beardless Irises comprise a large group, and their cultivation varies considerably with different species. Some do best in heavy loam, others in peat and loam, and others again in nearly all peat, formed into a sort of semi-bog, by the insertion of 3in. of clay beneath it. Some of the species which succeed with this latter preparation are: fulva, hexagona, loevigata, pseudacorus, setosa, sibirica and its varieties, and versicolor virginica. Examples of beardless Iris which succeed in loam, or loam and peat, are: aurea, graminea, Guldenstadtiana, humilis, Monnieri, ochroleuca, and spuria. I. iberica and I. susiana are two of the most singular and beautiful species, belonging to a separate group or sub-genus. They are amongst the most difficult of plants to flower, and require special treatment, apart from any of the others. A frame, and light, rich soil, should be provided for their accommodation, and they should be dried off, and allowed the fullest exposure to the sun from the time flowering is over, until spring of the following year. Plenty of river sand round the rhizomes tends to keep them dry in winter--an important point in the cultivation--and also assists in effecting perfect drainage at all times. All varieties of Iris are impatient of root disturbance, their flowering being much hindered thereby. Plants that are established increase in size rapidly, and flower with much more certainty if allowed to remain undisturbed. They like plenty of sun and air, but should be protected, if practicable, from east and northerly winds. In the subjoined list, the Synopsis of Mr. J. G. Baker, which appeared in the columns of the Gardeners' Chronicle, has been followed. Sect. I. Irises proper.

I. amoena (pleasing). A synonym of I. hybrida.

I. aphylla (leafless). fl. scentless; limb dark lilac, 2 1/2in. deep; falls obovate, 3/4in. to 1/4in. broad, reflexing half-way down, cuneately narrowed to a long claw; beard white; standards erect, a little broader than the falls, suddenly narrowed into a long claw; claws white, veined with lilac. May. l. not more than two produced to a tuft, glaucous-green, ensiform, falcate. Stems forked low down, or two or even three produced from the same tuft. h. 1ft. Eastern Europe and Western Asia. (B. M. 2361; B. R. 801, under name of I. furcata.) I. arenaria (sand-loving). fl. bright yellow, striped with purplish-brown on the claws; falls oblong-spathulate, with a bright yellow beard reaching half-way up; standards rather shorter, and narrow; scape slender, erect, one or two-flowered. May. l. tufted, few, linear. Rhizome much-branched. h. 3in. to 4in. Hungary to European Russia, 1802. This plant is well adapted for rockery or pot culture, but is not common in English gardens. (B. R. 549.) I. aurea (golden).* fl. bright yellow; falls oblong, crisped at the edge; standards oblanceolate, shorter than the falls. June. l. ensiform, about 2ft. long. Stem stout, bearing two sessile clusters of flowers. h. 3ft. to 4ft. Western Himalayas. (B. R. xxxiii. 59.) I. balkana (Balkan).* fl. bright lilac-purple; tube 1 1/4in. long; limb 3in. long; falls 1 1/4in., and standards 1 1/2in. broad; spathe valves green, acute. April. Stem as long as the leaves. h. 1ft. Northern Thrace, 1878. Mr. Baker regards this as a variety of I. Chamoeiris; it is a very fine plant. I. biflora (two-flowered).* fl. bright violet-purple; limb 2in. to 2 1/2in. deep; falls obovate, 1in. broad, reflexing half-way down, the yellow beard over 1in. long; standards erect, over 1in. broad; spathe two-flowered. April. l. ensiform, rather glaucous. Rhizome stout, short-creeping. South Europe, 1596. SYNS. I. fragrans, I. nudicaulis (under which name it is figured in B. M. 5806), I. subbiflora.

I. biglumis (two-plumed). A synonym of I. ensata.

I. Bloudovii (Bloudow's). fl. light yellow; limb almost 2in. long; outer segments obovate-cuneate, nearly or quite 1in. broad, reflexing half-way down, the bright yellow beard running more than half-way up; standards erect, as broad as the falls, but somewhat shorter; spathe two-flowered. May. l. linear, thin. h. 6in. to 12in. Altai Mountains. (R. G. 1020.) I. brachycuspis (short-pointed). A synonym of I. setosa. I. Chamaeiris (dwarf Iris).* fl. solitary; limb 2in. deep; falls oblong-spathulate, 3/4in. broad, bright yellow, tinged and veined with brown; beard bright orange-yellow; standards erect or converging, oblong-unguiculate, 1in. broad, crisped at the edge, primrose-yellow. April. l. four to six in a tuft, 3/8in. to 1/2in. broad, pale green. h. 4in. to 6in. South Europe. I. C. olbiensis (Olban). fl., limb deep lilac-purple, 2in. long; falls 1in. broad; claw white, veined with purple; beard white, tipped with yellow; standards obovate-unguiculate, a little broader than the falls. April. Stem 4in. to 6in. long, clasped by a sheathing leaf a little above the base. South of France. (B. M. 6110.) I. chinensis (Chinese). A synonym of I. japonica.

I. cretensis (Cretan).* fl., limb lilac, 2in. deep; falls obovate-unguiculate, beardless, 3/4in. broad; the reflexing lamina much shorter than the narrow claw; standards oblanceolate-unguiculate, 1/4in. broad. April and May. l. in dense tufts, narrow-linear, erect, firm, and stout in texture, acuminate, closely and distinctly ribbed. Stem none, so that the spathe is sessile in the centre of the cluster of leaves. Greece, Asia Minor, Crete, and the Ionian