Periballanthus involucratus Franchet & Savatier, Enum. Pl. Jap. 2: 524. 1878; Polygonatum platyphyllum Franchet.

Rhizome terete, 3--5 mm thick, slender. Stem arching, 20--50 cm, glabrous. Leaves 4--7, alternate; petiole short or indistinct; leaf blade broadly elliptic to ovate, usually 5--10 × 3--6 cm, glabrous, base rounded or tapering, apex acute to shortly acuminate. Inflorescences 2-flowered; peduncle 1--2 cm, glabrous; bracts 2, borne at base of pedicel, ovate to broadly ovate-elliptic, 2--3.5 × 1--3 cm, leaflike, 7- or more veined, persistent. Flowers pendulous; pedicel 1--2 mm, glabrous. Perianth greenish white, cylindric, 2.3--2.5 cm; lobes ca. 3 × 2 mm. Filaments ± compressed, 2--4 mm, papillose; anthers 3--5 mm. Ovary ca. 5 mm. Style 1.8--2 cm, slightly exserted. Berries ca. 1 cm in diam., 7- or 8-seeded. Fl. May--Jun, fr. Aug--Sep. 2 n = 18*, (20, 22).

Polygonatum cryptanthum H. Léveillé & Vaniot (Repert. Spec. Nov. Regni Veg. 5: 282. 1908), from small islands between Korea and Japan (Kyushu), is often considered to be conspecific with P. involucratum (e.g., by Jeffrey, Kew Bull. 34: 435--471. 1980). However, the former differs from the latter in its papillose peduncle, pedicels, and abaxial leaf and bract surfaces, shape and size of flowers, shape of filaments, and length of style in relation to perianth. In this treatment, P. cryptanthum is regarded as an independent species and is excluded from the synonymy of P. involucratum.

Forests, shaded and moist slopes; 700--1400 m. Hebei, Heilongjiang, Henan, Jilin, Liaoning, ?Nei Mongol, ?S Shaanxi (Qin Ling), Shanxi [Japan, Korea, Russia (Far East)].