《中国植物志》|| 紫草科 BORAGINACEAE ||软紫草属 Arnebia Forssk. ||软紫草 Arnebia euchroma (Royle) I. M. Johnst.

6．软紫草 新疆紫草（中药鉴别手册）
Arnebia euchroma (Royle) Johnst. in Contr. Gray Herb. 73: 49. 1924; Riedl in Reching Fl. Iranica 48: 164. 1967; Kazmi in Journ. Arn. Arb. 52: 486. 1971; 中国高等植物图鉴3: 550. 图5054. 1974; 朱格麟, 植物分类学报20: 3. 328. 1982.——Lithospermum euchromon Royle, Illustr. Bot. Himal. Mount. 1: 305. 1839.——Macrotomia endochroma Hook. f. et Thoms. ex Henderson et Hume in Lahore to Yarkand 328. 1873, nomen nudum.——M. cuchroma (Royle) Paulsen, Bot. Tidskr. 27: 216. 1906; M. Pop. in Fl.. URSS 19: 169. 1953.
多年生草本。根粗壮，直径可达2厘米，富含紫色物质。茎1条或2条，直立，高15-40厘米，仅上部花序分枝，基部有残存叶基形成的茎鞘，被开展的白色或淡黄色长硬毛。叶无柄，两面均疏生半贴伏的硬毛；基生叶线形至线状披针形，长7-20厘米，宽5-15毫米，先端短渐尖，基部扩展成鞘状；茎生叶披针形至线状披针形，较小，无鞘状基部。镰状聚伞花序生茎上部叶腋，长2-6厘米，最初有时密集成头状，含多数花；苞片披针形；花萼裂片线形，长1.2-1.6厘米，果期可达3厘米，先端微尖，两面均密生淡黄色硬毛；花冠筒状钟形，深紫色，有时淡黄色带紫红色，外面无毛或稍有短毛，筒部直，长1-1.4厘米，檐部直径6-10毫米，裂片卵形，开展；雄蕊着生于花冠筒中部（长柱花）或喉部（短柱花），花药长约2.5毫米；花柱长达喉部（长柱花）或仅达花筒中部（短柱花），先端浅2裂，柱头2，倒卵形。小坚果宽卵形，黑褐色，长约3.5毫米，宽约3毫米，有粗网纹和少数疣状突起，先端微尖，背面凸，腹面略平，中线隆起，着生面略呈三角形。花果期6-8月。
产新疆及西藏西部。生海拔2500-4200米砾石山坡、洪积扇、草地及草甸等处。印度西北部、尼泊尔、巴基斯坦、克什米尔地区、阿富汗、伊朗、苏联中亚地区及西伯利亚有分布。
根富含紫草素，可代紫草入药，功效同紫草。

《Flora of China》|| Boraginaceae || Arnebia ||软紫草 Arnebia euchroma

6. Arnebia euchroma (Royle) I. M. Johnston, Contr. Gray Herb. 73: 49. 1924.

软紫草 ruan zi cao

Lithospermum euchromon Royle, Ill. Bot. Himal. Mts. 1: 305. 1839; Macrotomia euchroma (Royle) Paulsen.

Herbs perennial. Roots stout, to 2 cm in diam., containing copious purple dye. Stems usually 1 or 2, erect, branched above, sheathed with remaining bases of leaves, 15-40 cm tall, spreading white or pale yellow hirsute. Leaves sessile, sparsely semiappressed hirsute. Basal leaves linear to linear-lanceolate, 7-20 × 0.5-1.5 cm, base sheathlike, apex short acuminate; stem leaves lanceolate to linear-lanceolate, smaller without sheathlike base. Cymes terminal, 2-6 cm at anthesis, many flowered; bracts lanceolate. Flowers heterostylous. Calyx lobes linear, 1.2-1.6 cm, to 3 cm in fruit, densely pale yellow hirsute on both sides, apex subacute. Corolla dark purple, sometimes pale yellow and purple-red tinged, tubular-campanulate, glabrous or sparsely short pubescent outside; tube straight, 1-1.4 cm; limb 6-10 mm wide; lobes spreading, ovate. Anthers ca. 2.5 mm. Style apex 2-lobed; stigmas 2, obovate. Nutlets black-brown, broadly ovate, ca. 3.5 × 3 mm, scabrous reticulate lined, with few tubercles, adaxially almost flat, center line prominent, abaxially convex, apex subacute; attachment scar somewhat triangular. Fl. and fr. Jun-Aug.

Rocky slopes, gravelly marshes, meadows. Xinjiang, W Xizang [Afghanistan, NW India, Kazakhstan, Kyrgyzstan, Nepal, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; SW Asia]

The roots are used medicinally.