Iris versicolor. Blue Flag, or Flower de luce.

Pl. 16. Iris versicolor IN the Hortus Elthamensis, published by John J. Dillenius in 1732, there are figures of two plants under the name of "Iris Americana versicolor," the one with an entire, the other with a crenate style. To one of these, the plant represented in our plate apparently belongs. This plant however is so subject to variation in the colour of its flowers, the crenatures and direction of its stigmas, &c. that it has received from different botanists dissimilar names. The Linnaean characters of Iris versicolor and Virginica are hardly sufficient to distinguish them from each other. Our plant is the Iris versicolor of Muhlenburgh's catalogue, by his own declaration. In the character of its stem however, it agrees equally well with Iris virginica of Linnaeus and Michaux. It may be doubted whether the plant figured in the Botanical Magazine, t. 703, is more than a variety of this species. The characters taken from the comparative length of the stem and leaves, of the inner petals and stigmas, and the direction of the stem and of the stigmas; are all subject to variation. Michaux, Elliott and Pursh make the Virginica synonymous with Iris hexagona of Walter, which seems permanently distinguished by the deep furrows in the angles of its capsule.

The Iris versicolor is found throughout the United States in the borders of swamps and in wet meadows, of which it forms a principal ornament in the month of June. No race of vegetables can be better marked than the elegant genus to which this plant belongs. They are essentially distinguished by a corolla, parted into six segments or petals, of which three are reflexed and three are erect. The stigmas resembling petals. The species in our plate has ensiform leaves, its stem acute on one side, its capsules oblong, three sided, with obtuse angles.

Class Triandria,—Order Monogynia.—Natural orders, Ensatae, Lin. Irides, Juss.

The root is fleshy, horizontal, sending down a multitude of fibres. Stem two or three feet high, round on one side, acute on the other, frequently branched, and bearing from two to six flowers. Leaves sword shaped, striated, sheathing at base. Bractes becoming scarious. Peduncles of various length, flattened on the inside. Germ three cornered, with flat sides and obtuse angles. Outer petals of the flower spatulate, beardless, the border purple, the claw variegated with green, yellow and white, and veined with purple. Inner petals erect, varying in shape from spatulate to lanceolate, usually paler than the outer, entire or emarginate. Style short, concealed; stigmas three, petal-form, purple or violet, resting on the outer petals, their extremeties bifid, crenate, and more or less reflexed; their lower lip short. Stamens concealed under the stigmas, with oblong-linear anthers. Capsule three celled, three valved; when ripe, oblong, turgid, three sided, with roundish angles. Seeds numerous, flat.

The young leaves of this and some other species of Iris, afford an excellent view of the spiral filament, which lines the sap vessels of the leaf. If a leaf, which has just emerged from the ground, be carefully broken across, and the segments gradually drawn asunder, these fine filaments will unroll themselves, and their spiral structure become very obvious to the microscope.

The root of the Iris versicolor has a nauseous taste, and when swallowed or held in the mouth, even in small quantities, it leaves behind a powerful sense of heat and acrimony in the fauces. Its most active chemical constituent appears to be a resin, which separates in the form of a white precipitate, when water is added to the alcoholic solution. The decoction suffers little or no change with alcohol, gelatin or salts of iron. Muriate of tin affects it slightly, the nitrate of mercury more abundantly. Its taste is much weaker than that of the tincture. Water distilled from the root has a highly nauseous taste and odour.

The root of the Iris versicolor given medicinally is an active cathartic. Mr. William Bartram, in his travels in Georgia and Florida, informs us, that on his arrival at Ottasse, an Indian town on the Tallapoose, he found the natives "fasting, taking medicine, and praying, to avert a grevious calamity of sickness which had lately afflicted them, and laid in the grave abundance of their citizens. The first seven or eight days, during which time they eat or drink nothing, but a meagre gruel made of a little corn-flour and water; taking at the same time, by way of medicine or physic, a strong decoction of the roots of the Iris versicolor, which is a powerful cathartic. They hold this root in high estimation, and every town cultivates a little plantation of it, having a large artificial pond just without the town, planted and almost overgrown with it."

Having myself formerly made use of this root in dispensary practice, I can bear testimony to its efficacy as a medicine, though not altogether to its convenience. A small quantity of the recent root, or a few grains of the root newly dried, are generally certain and active in their operation on the bowels. They are however apt to occasion a distressing nausea like sea sickness, with a prostration of strength of some hours' continuance; so that I think the plant will not be like to come into favor as a cathartic, at least when better ones are at hand. The activity of this article is diminished by age.

The stimulating properties of the Iris render it capable of exciting many of the secretions, as well as excretions. But I know of no purpose for which it seems better calculated, than that of a diuretic. The late Dr. Macbride of Carolina assured me, that he had found great benefit in dropsical affections from a decoction of the roots of this plant in combination with those of Eryngium yuccifolium. In consequence of his recommendation, I administered the tincture of the Iris in small doses to several persons affected with anasarca and with hydrothorax. It was evidently of service to a majority of those who took it, for a certain time. That it did not always cure the disease, is a reproach which it must divide with diuretic remedies of much older celebrity.

The Iris gracilis, a species described in the Florida Bostoniensis, the Iris pseudacorus of Europe, and several others of the genus, appear to possess properties very similar to those of the plant described.

Botanical References.

Iris versicolor, Lin. Sp. pl.
Dillenius, Elth. t. 155.
Curtis, Bot. Mag. t. 21, a variety.
Pursh, i. 29.
Elliott, Car. i. 45.
Walter, Car. 67.

Medical References.

Bartram, travels, 454, Lond. edit.
Cutler, Mem. Amer. Acad. 405-6.
Macbride, in Elliott's Car. i. 45.

American Medical Botany, 1817-1821, was written by Jacob Bigelow, M. D.