Siebold's Spurge

Euphorbia sieboldiana varies very much, especially in the 2 gland horns, which are either obtuse or acute. However, plants have in common the large rhizome, involucral leaves, and capsule, as well as the seeds.

The rhizome is used medicinally.

Herbs, (22-)40-70 cm tall. Rootstock extensively rhizomatous, 10-20 cm, rhizomes 4-15 mm thick, segmented/moniliform. Stems single or clustered, (2-)4-7 mm thick, often with branchlets from upper nodes, smooth and glabrous. Leaves alternate, progressively larger toward apex; stipules absent; basal scale-leaves soon lost; petiole absent or nearly so; leaf blade elliptic, obovate-lanceolate, or oblong-elliptic, very variable, 2-5(-10) × 0.5-1.5(-3) cm, glabrous, base attenuate or cuneate, (crenulate or) entire, apex obtuse, acute, or acuminate; lateral veins pinnate. Inflorescence a terminal pseudumbel; primary involucral leaves 3-5(or 6), elliptic or ovate-elliptic, 1.5-2.5(-4.2) cm × 0.4-0.8(-2.8) mm, base subtruncate, apex obtuse, primary rays 3-5(or 6), 2-4(-7) cm; cymes mostly dichasial, sometimes becoming monochasial; cyathophylls 2, very variable, reniform-rounded, ovate-triangular, or rounded, 0.8-1.4(-1.8) × 0.8-1.6(-3.2) cm, base very broadly cuneate, shallowly cordate, or subrounded, apex rounded. Cyathium shortly stalked; involucre cuplike, 3-4 × 3-5 mm, lobes triangular or ovate-triangular, shortly pilose inside; glands 4, mainly yellow-brown, sometimes pale yellow or yellow-green, crescent-shaped, tips extended into 2 slender horns, horns obtuse to needlelike, very variable. Male flowers many, exserted from involucre. Female flower: ovary exserted from cup, smooth, glabrous; styles connate for less than 1/4 length, persistent but easily lost; style arms 2-lobed. Capsule 3-lobed, (3-)3.5-4 × 4-5 mm, smooth, glabrous. Seeds subterete-globose, ca. 2.5 × 1.5 mm, gray-brown, smooth; caruncle present, small, sessile. Fl. and fr. Apr-Sep.

Fields, scrub, forest margins, sparse forests, grasslands. Throughout China except Fujian, Hainan, Nei Mongol, Qinghai, Taiwan, Xinjiang, Xizang [Japan, Korea, Russia (Far East)].

Euphorbia bodinieri H. Léveillé; E. erythraea Hemsley; E. esquirolii H. Léveillé & Vaniot; E. glaucopoda Diels; E. henryi Hemsley; E. hippocrepica Hemsley; E. kangdingensis W. T. Wang; E. kangdingensis var. puberula W. T. Wang; E. luticola Handel-Mazzetti; E. savaryi Kiss; E. szechuanica Pax & K. Hoffmann.

Euphorbia sieboldiana, the Siebold's spurge, is a species of flowering plant in the spurge family Euphorbiaceae. It is native to eastern Asia, where it is found in China, Japan, Korea, and eastern Russia. Its natural habitat is in grassy areas and forest margins. It is a common species in Japan.

It is an rhizomatous perennial growing to 70 cm tall. It produces small flowers in compact pseudoumbels. These lack petal-like appendages. This species can be readily identified by the horn-like projections on the glands of the involucre. Blooming time is in spring and early summer.