Perennials, 20-80 cm tall, glabrous except for inflorescences. Stems erect, often apically branched. Leaves usually numerous and alternate, rarely basal ones whorled, rarely all in whorls of 4; leaf blade linear, 2-8 X 0.2-1.5 cm, veins 1(-3). Inflorescences racemose, flowers crowded, axis elongating in fruit; axis and pedicels glabrous to densely with short glandular hairs; bracts linear to narrowly lanceolate, longer than pedicel. Pedicel 2-8 mm. Calyx glabrous or inside sparsely glandular hairy; lobes lanceolate to ovate-lanceolate. Corolla yellow, 1-1.5 cm (excluding spur); spur 1-1.5 cm, slightly curved; lateral lower lip lobes ovate-orbicular, 3-4 mm wide, middle lobe ligular; upper lip longer than lower lip, lobes ca. 2 mm, ovate. Capsule ovoid-globose. Seeds disclike, margin broadly winged, center verrucose when mature. Fl. Jun-Sep.
"Perennial, 3–8 dm, colonial by creeping roots; lvs very numerous, pale green, 2–5 cm × 2–4 mm, narrowed below to a petiole-like base; fls numerous in a compact spike, yellow with orange palate, 2–3.5 cm, including the spur; fr round-ovoid, 8–12 mm; seeds winged; 2n=12. Native of Europe, established in fields, roadsides, and waste places throughout temperate N. Amer. May–Sept. (L. linaria)"
Herb, up to 250 mm tall. Leaves opposite, verticillate or alternate, sublinear, sessile, entire. Flowers arranged in dense, terminal racemes, spurred. Flowers yellow.
Perennial herb, 0.25-0.92 m high. Stems erect, simple or branched at base or above in racemes, glabrous, sometimes glandular-pubescent in inflorescence. Leaves opposite, verticillate or mostly alternate; sessile; blade sublinear, narrowly elliptical or oblanceolate, 20-60 x 1-5(-15) mm, apex acute, margins entire. Flowers: in dense, terminal racemes; spur conical, 10-13 mm long, acute, corolla tube 19-33 mm long, 10 mm wide at mouth; corolla yellow, palate usually orange, bearded; Oct.-Dec.