Orostachys spinosa (L.) Meyer ex A. Berger

Chinese dunce cap (Orostachys spinosa) is a slow-growing, fleshy-leafed succulent in the family Crassulaceae. It is found in arid areas in Mongolia, Russia, China, and Kazakhstan and is remarkably hardy, thriving in temperatures as low as -40 degrees C (-40 F) and able to photosynthesize under a thin layer of snow. A fully-grown Chinese dunce cap resembles a sunflower head 10 cm (4 inches) across, with a flattened dome of spiral, tightly closed leaves surrounded by a ring of upright leaves. When the plant is mature, which takes about five years, it produces the conical flower stalk responsible for its common name and dies afterwards. Like other members of the Crassulaceae, O. spinosa copes with arid conditions by fixing carbon using the CAM (Crassulacean acid metabolism) pathway: it keeps stomata on the leaves closed during the day to minimize evaporative water loss but opens them at night to absorb carbon dioxide and store it for photosynthesis during the day. It is the most cold-tolerant CAM plant known. Orostachys spinosa is used in Mongolian herbal medicine, as forage for livestock in winter, and in decorative rock gardens (Oyungerel 2008). 

Rosette leaves crowded, oblong; appendage white, suborbicular, cartilaginous, apical spine 2-4 mm. Stem leaves broadly linear to oblanceolate, 1-3 × 0.2-0.5 cm, apex acuminate, apical prickle cartilaginous. Flowering stem 10-30 cm. Inflorescence terminal, spicate or racemose, 5-20 cm; bracts lanceolate to oblong, to 4 mm, apex spinose; pedicels ca. 1 mm or absent. Sepals red spotted, ovate-oblong, 2-3 mm, apex spinose. Petals yellowish green, ovate-lanceolate, 5-7 × ca. 1.5 mm, base connate for ca. 1 mm, apex acuminate. Stamens slightly longer than petals; anthers yellow. Nectar scales subquadrangular, apex emarginate. Follicles erect, ellipsoid-lanceolate, base narrowed, apical beak ca. 1.5 mm. Seeds oblong-ovoid. Fl. Jul-Aug, fr. Sep.

Gansu, Heilongjiang, Jilin, Liaoning, Nei Mongol, Xinjiang, Xizang [Korea, Mongolia, Russia].

Rock crevices on dry slopes; 600-2900 m.

Cotyledon spinosa Linnaeus, Sp. Pl. 1: 429. 1753; C. erubescens (Maximowicz) Franchet & Savatier; Orostachys erubescens (Maximowicz) Ohwi; Sedum erubescens (Maximowicz) Ohwi; S. spinosum (Linnaeus) Thunberg; Umbilicus erubescens Maximowicz.

Orostachys spinosa là một loài thực vật có hoa trong họ Crassulaceae. Loài này được (L.) Sweet miêu tả khoa học đầu tiên năm 1830.

黄花瓦松（学名：Orostachys spinosus）是景天科瓦松属的植物。分布在朝鲜、俄罗斯、蒙古以及中国大陆的黑龙江、内蒙古、辽宁、甘肃、吉林、新疆、西藏等地，生长于海拔600米至2,900米的地区，多生于干山坡石缝中，目前尚未由人工引种栽培。