Herbs with equitant leaves and perfect flowers. The 6 petal-like divisions of the perianth in 2 (similar or dissimilar) sets of 3 each; the tube adherent to the 3-celled ovary. Stamens 3, distinct or monadelphous, opposite the 3 stigmas, and with anthers extrorse, that is, on the outside of the filaments, facing the divisions of the perianth and opening on that side. Flowers from leafy bracts. (See Part I., sections 88 and 89.)
1. Iris. The 3 outer divisions of the perianth reflexed, the 3 inner erect and smaller. Stamens distinct, the anther of each concealed under a flat and petal-like arching stigma. The styles below adherent to the tube of the perianth. Pod 3-angled. Flowers blue, large and showy. Leaves sword-shaped or grass-like.
2. Sisyrin'chium. The 6 divisions of the perianth alike, spreading.
Stamens monadelphous. Stigmas thread-like. Pod globular, 3-angled. Stems 2-edged. Leaves grass-like. Flowers blue, clustered, from 2 leafy bracts. Plants low and slender.
1. I. versic'olor, L. (Larger Blue Flag.) Stem stout and leafy, from a thickened rootstock. Leaves sword-shaped, Flowers violet-blue, 2 or 3 inches long. Inner petals much smaller than the outer. - Wet places.
2. I. prismat'ica, Pursh. (Slender. Blue Flag.) Distinguished from the last by its very slender stem and narrowly linear leaves. Tube of the flower very short. - Atl. sea-coast.
3. I. laeus'tris, Nutt. (Lake Dwarf Iris.) Stem low, 3-6 inches high. Inner petals nearly equal to the outer. Tube of the perianth slender, less than an inch long, dilated upwards, rather shorter than the divisions of the perianth. Leaves lanceolate, 3-5 inches long. - Shore of Lake Huron.
1. S. angustifo'lium, Mill. (S. Bermudiana, var. mucro-natum, Gray.) A pretty little plant, rather common in moist meadows among grass. The divisions of the delicate blue perianth obovate, notched at the end, and bristle-pointed from the notch. The spathe solitary. Roots fibrous.
2. S. anceps, Cav., (S. Bermudiana, var. anceps, Gray.) has the scape 6-18 inches high, and usually bearing 2 or more peduncled spathes.