Illinois pinweed Illinois pinweed

Herbs, perennial. Stems: basal produced; flowering erect, 25–40 cm, sparsely sericeous. Leaves of flowering stems opposite to subopposite; blade linear-lanceolate to narrowly oblanceolate, 10–20 × 1–1.5 mm, apex acute, <usually indurate>, abaxial surface sparsely pilose on midvein and margins, adaxial glabrous. Pedicels 1 per axil, 1–2 mm. Flowers: calyx 1.8–2 mm, <indurate, shiny, yellow-brown basally in fruit>, outer sepals shorter than or equaling inner. Capsules ellipsoid to ovoid, 1.5–2 × 1–1.2 mm, ± equaling to slightly longer than calyx. Seeds (1–)2(–3).

Flowering summer; fruiting late summer–fall. Old fields, woodland margins, other dry, sandy, open sites; 10–400 m; Ala., Conn., Del., D.C., Ga., Ind., Iowa, Ky., La., Md., Mo., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Va., W.Va.