Herbs to 1 m tall, perennial, slightly anisophyllous. Stems 4-angled, sulcate, glabrous. Petiole (1.5-)4-8 cm, glabrous; leaf blade elliptic, (4.5-)11-17 × (2.5-)7-10 cm, both surfaces glabrous, abaxially paler, adaxially green and with numerous cystoliths, secondary veins (6-)9-12 on each side of midvein, base subrounded and decurrent onto petiole, margin dentate, apex acute. Inflorescences axillary, branched spikes, bearing a pair of reduced leaves at branching point and forming a lax terminal panicle of spikes, ultimate branches slightly zigzag; bracts spatulate-linear, 2-3 mm, persistent, glabrous, both surfaces with abundant white cystoliths; bracteoles linear, ca. 3 mm. Flowers only one fertile per pair. Calyx ca. 1 cm, glabrous, outside densely covered with white cystoliths, inside with cystoliths in 2 lines along lobe margin, 5-lobed to ca. 2 mm from base; lobes linear, equal. Corolla blue, ca. 3.8 cm, ventricose, outside glabrous, inside glabrous except for trichomes retaining style; tube basally cylindric and ca. 2 mm wide for ca. 1.2 cm, bent to ca. 45° at middle, and gradually widened to ca. 1 cm at mouth. Stamens 4; filaments included, shorter pair ca. 6 mm, longer pair ca. 8 mm; anther thecae oblong, ca. 2 mm. Ovary glabrous; style ca. 2.7 cm, pilose. Capsule ca. 1.6 cm, glabrous, 4-seeded, apex with a ca. 4 mm beak. Seeds ovate in outline, ca. 2 × 2 mm, appressed pilose; areola small. Fl. Aug-Sep, fr. Nov.
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