Subshrubs to 3 m tall, isophyllous or slightly anisophyllous, blackish green when dry. Stems branched, 4-angled, sulcate, glabrous, densely covered with white prominent cystoliths; nodes pustulose, pubescent. Petiole 2-5 cm, bifariously pubescent; leaf blade ovate-elliptic, 9-22 × 5.5-14 cm, abaxially paler green and glabrous, adaxially green, subglabrous with sparse large-celled trichomes, and sparsely covered with prominent cystoliths especially along veins, secondary veins 6-10 on each side of midvein, prominent on both surfaces, curved, and netted near margin, tertiary veins conspicuous, base decurrent onto petiole, margin crenulate, apex acute to long acuminate. Inflorescences axillary, shortly pedunculate spikes, 1-3(-6) cm, 2(-8)-flowered but commonly reduced to a subcapitate flower pair; rachis gland-tipped pubescent; bracts linear-lanceolate, 9-14 × 2-3 mm, abaxially gland-tipped pubescent, adaxially glabrous; bracteoles linear-lanceolate, 9-13 × ca. 2.5 mm, abaxially gland-tipped pubescent, adaxially glabrous. Flowers paired. Calyx 1-1.5 cm, outside gland-tipped pubescent, inside glabrous, 2-lipped; lower lip 2-lobed almost to base, lobes linear-lanceolate, 9-14 × 2-3 mm, and apex acute; upper lip with 3 lanceolate 5-7 mm teeth connate for 4-7 mm. Corolla purplish blue, 3-4 cm, straight, outside glabrous, inside glabrous except for trichomes retaining style; tube ca. 2 mm wide at base then gradually widened to ca. 2 cm at mouth; lobes ovate, ca. 1 × 1 cm, apex emarginate. Stamens 4, included; filaments basally pubescent, shorter pair ca. 6 mm, longer pair ca. 8 mm; anther thecae oblong; pollen type 3. Ovary not examined; style ca. 2 cm, glabrous. Capsule not seen. Fl. Apr, Jun, Nov.
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