8. Obolaria. Calyx of 2 foliaceous sepals. Corolla 4-lobed, oblong-campanulate.
Suborder II. Menyantheæ. Leaves all alternate and mostly petioled, sometimes trifoliolate or crenate. Æstivation of corolla induplicate-valvate. Marsh or aquatic perennials.
9. Menyanthes. Corolla bearded inside. Leaves 3-foliolate.
10. Limnanthemum. Corolla naked, or bearded on the margins only. Leaves simple, rounded.
1. ERYTHRÆ̀A, Richard. Centaury.
Calyx 4–5-parted, the divisions slender. Corolla funnel-form or salver-form, with slender tube and 4–5-parted limb. Anthers exserted, erect, twisting spirally. Style slender, single; stigma capitate or 2-lipped.—Low and small branching annuals, chiefly with rose-purple or reddish flowers (whence the name, from ἐρυθρός, red); in summer.
E. Centaùrium, Pers. (Centaury.) Stem upright (6–12´ high), corymbosely branched above; leaves oblong or elliptical, acutish, the basal rosulate, the uppermost linear; cymes clustered, flat-topped, the flowers all nearly sessile; tube of the (purple-rose-colored) corolla not twice the length of the oval lobes.—Waste grounds, shores of Lakes Ontario and Michigan. (Adv. from Eu.)
E. ramosíssima, Pers. Low (2–6´ high); stem many times forked above and forming a diffuse cyme; leaves ovate-oblong or oval, not rosulate below; flowers all on short pedicels; tube of the (pink-purple) corolla thrice the length of the elliptical-oblong lobes.—Wet or shady places, N. J., E. Penn., and southward. (Nat. from Eu.)
E. spicàta, Pers. Stem strictly upright (6–10´ high); the flowers sessile and spiked along one side of the simple or rarely forked branches; leaves oval and oblong, rounded at base, acutish; tube of the (rose-colored or whitish) corolla scarcely longer than the calyx, the lobes oblong.—Sandy sea-shore, Nantucket, Mass., and Portsmouth, Va. (Nat. from Eu.)
2. SABBÀTIA, Adans.