OTHER COMMON NAMES—Iris, flag-lily, liver-lily, snake-lily, poison-flag, water-flag, American fleur-de-lis or flower-de-luce.
HABITAT AND RANGE—Blue Flag delights in wet, swampy localities, making its home in marshes, thickets, and wet meadows from Newfoundland to Manitoba, south to Florida and Arkansas.
DESCRIPTION OF PLANT—The flowers of all of the species belonging to this genus are similar, and are readily recognized by their rather peculiar form, the three outer segments or parts reflexed or turned back and the three inner segments standing erect.
Blue Flag is about 2 to 3 feet in height, with an erect stem sometimes branched near the top, and sword shaped leaves which are shorter than the stem, from one-half to 1 inch in width, showing a slight grayish "bloom" and sheathing at the base. This plant is a perennial belonging to the iris family (Iridaceae), and is a native of this country. June is generally regarded as the month for the flowering of the Blue Flag, altho it may be said to be in flower from May to July, depending on the locality. The flowers are large and very handsome, each stem bearing from two to six or more. They consist of six segments or parts, the three outer ones turned black and the three inner ones erect and much smaller. The flowers are usually purplish blue, the "claw" or narrow base of the segments, variegated with yellow, green, or white and marked with purple veins.
All of the species belonging to this genus are more or less variegated in color; hence the name "iris," meaning "rainbow," and the specific name "versicolor," meaning "various colors." The name "poison-flag" has been applied to it on account of the poisonous effect it has produced in children, who, owing to the close resemblance of the plants before reaching the flowering stage, sometimes mistake it for sweet flag.
The seed capsule is oblong, about 1 1/2 inches and contains numerous seeds.
DESCRIPTION OF ROOTSTOCK—Blue Flag has a thick, fleshy, horizontal rootstock, branched, and producing long, fibrous roots. It resembles sweet-flag (Calamus) and has been mistaken for it. The sections of the rootstock of Blue Flag, however, are flattened above and rounded below; the scars of the leaf sheaths are in the form of rings, whereas in sweet-flag the rootstock is cylindrical and the scars left by the leaf sheaths are obliquely transverse. Furthermore, there is a difference in the arrangement of the roots on the rootstock, the scars left by the roots in Blue Flag being close together generally nearer the larger end, while in sweet-flag the disposition of the roots along the rootstock is quite regular. Blue Flag is grayish brown on the outside when dried, and sweet-flag is light brown or fawn colored. Blue Flag has no well-marked odor and the taste is acrid and nauseous, and in sweet-flag there is a pleasant odor and bitter, pungent taste.
COLLECTION, PRICES AND USES—Blue Flag is collected in autumn and usually brings from about 7 to 10 cents a pound. Great scarcity of Blue Flag root was reported from the producing districts in the autumn of 1906. It is an old remedy, the Indians esteeming it highly for stomach troubles, and it is said that it was sometimes cultivated by them in near-by ponds on account of its medicinal value. It has also been used as a domestic remedy and is regarded as an alterative, diuretic and purgative. It was official in the United States Pharmacopoeia of 1890.
Ginseng and Other Medicinal Plants, 1936, was written by A. R. Harding.