Rhynchoglossum sasakii Hayata, Icon. Pl. Formos. 6: 34. 1916; Oshimella formosana Masamune & Suzuki; O. sasakii (Hayata) Masamune & Suzuki.

Stems 18-50 cm, ascending, basally procumbent, brownish puberulent, glabrescent. Normal leaves sessile or petiole to 2(-3) mm; leaf blade green or greenish, oblique, ovate to ovate-oblong, 1.8-10.5 X 0.6-3.5 cm, adaxially sparsely puberulent, abaxially sparsely puberulent along veins, base strongly oblique, cuneate on narrow side, rounded, subcordate, or cuneate on other, margin indistinctly denticulate to serrate, apex acuminate; reduced leaf blade ovate to lanceolate, 0.5-1.5 cm. Cymes axillary; peduncle 0.8-4.5 cm, sparsely white or brown puberulent. Calyx 5-sect from base; segments ovate, 2.5-3.5 X 1.8-3 mm, outside glabrescent. Corolla white, 0.8-1.5 cm, outside glabrous, inside sparsely puberulent below abaxial lip; tube subtubular, 4-7 X 4-6 mm; adaxial lip 1.5-2 mm; abaxial lip 4-8 mm. Filaments 2-2.5 mm, puberulent; anthers ca. 0.6 mm wide; staminode ovate, ca. 0.6 mm. Pistil ca. 2.2 mm, glabrous. Style 1-2 mm; stigma 1, orbicular. Capsule 2-4 mm in diam. Fl. Jun-Sep, fr. Sep-Oct.

Whytockia sasakii is unusual in having ovaries 2-loculed basally and 1-loculed above.

* Forests on wet hillsides and streambanks; 500-1900 m. Taiwan.