Stems simple or branched, 7–120 cm; branches ascending, spreading, or arching, quadrangular-ridged to winged distally, glabrate or scabridulous to sparsely scabrous, especially on angles or also on faces near nodes. Leaves spreading to ascending; blade narrowly linear to linear or linear-lanceolate, 7.5–50 × 0.5–4(–5) mm, not fleshy, margins entire, abaxial midvein sometimes scabrous, adaxial surface scabrous; axillary fascicles absent or shorter than subtending leaves. Inflorescences racemes, short to elongate, flowers 1 or 2 per node; bracts longer than pedicels. Pedicels spreading-ascending, 1–5(–6) mm, glabrous, rarely scabrous. Flowers: calyx tubular-campanulate to hemispheric, tube (2–)3–5 mm, glabrous, rarely scabrous on major veins, lobes triangular, lanceolate, or triangular-subulate, not keeled, 0.8–3(–5) mm; corolla pink to rosy pink, with 2 yellow lines and red spots in abaxial throat or these pale or absent, 9–36 mm, throat pilose externally and villous within across bases and sinus of adaxial lobes, lobes: abaxial spreading to reflexed or projected to somewhat spreading (small-flowered plants), adaxial erect to reflexed, 2.5–11 mm, pilose externally; proximal anthers parallel to filaments, distal oblique or perpendicular to filaments (parallel in small-flowered plants), pollen sacs 0.9–4.5 mm; style included or exserted, 6.5–21 mm. Capsules globular, 4–6(–7) mm. Seeds dark brown, 0.7–1.4 mm. 2n = 28.