In botany this is the generic name of a number of beautiful plants
belonging to the natural order of _Iridaceæ_. The plants have a
creeping rootstock, or else a flat tuber, equitant leaves, irregular
flowers, and three stamens. They are represented equally in the
temperate and hotter regions of the globe. The wild species of iris are
generally called blue-flag, and the cultivated flower-de-luce, from
the French _fleur de Louis_, it having been the device of Louis VII.
of France. Our commonest blue-flag, _Iris versicolor_, is a widely
distributed plant, its violet-blue flowers, as may be seen, upon stems
one to three feet high, being conspicuous in wet places in early
summer. The root of this possesses cathartic and diuretic properties,
and is used by some medical practitioners. The slender blue-flag found
in similar localities near the Atlantic coast, is smaller in all its
parts. A yellowish or reddish-brown species, resembling the first named
in appearance, is found in Illinois and southward. There are three
native species which grow only about six inches high and have blue
flowers. They are found in Virginia and southward, and on the shores of
the great lakes; these are sometimes seen as garden plants. The orris
root of commerce is the product of _Iris Florentina_, _I. pallida_,
and _I. Germanica_, which grow wild in the south of Europe; the
rhizomes are pared and dried, and exported from Trieste and Leghorn,
chiefly for the use of perfumers; they have the odor of violets. The
garden species of iris are numerous, and by crossing have produced a
great many known only by garden names. The dwarf iris, _I. pumila_,
from three to six inches high, flowers very early and makes good
edgings to borders; the common flower-de-luce of the gardens is _I.
Germanica_; the elder-scented flower-de-luce is _I. sambucina_. These
and many others are hardy in our climate, and readily multiplied by
division of their rootstocks. The mourning or crape iris is one of the
finest of the genus, its flowers being very large, dotted and striped
with purple on a gray ground. The flowers of most of the species are
beautiful. Some of them have received much attention from florists,
particularly the Spanish, English, and German, or common iris, all
corm-rooted species, and all European. The Persian iris is delightfully
fragrant. The roots of all these species are annually exported in
considerable quantities from Holland. The roasted seeds of one species
have been used as a substitute for coffee.