石油菜 shi you cai

Herbs perennial, stoloniferous, glabrous, dioecious. Stems blue-green when dry, erect, much branched, 5-40 cm tall, 1.5-5 mm in diam., somewhat succulent, with dense cystoliths. Leaves crowded on apex of stem and branches; stipules persistent, deltoid, ca. 1 mm, membranous; petiole subequal in length, 0.5-2 cm; leaf blade abaxially gray-green, broad-ovate, rhombic-ovate, or suborbicular, subequal in size, 8-20 × 6-18 mm, succulent, papery when dry, 3-veined, lateral pair reaching margin in middle, secondary veins 2-3 each side, inconspicuous, honeycombed abaxially, cystoliths linear, conspicuous adaxially, sometimes on both surfaces, and often longitudinally arranged along margins on both surfaces, base broadly cuneate, subrounded, or subtruncate, often with small auricle, margin entire, rarely undulate or bluntly crenate, apex obtuse, acute, or subrounded. Inflorescences solitary, in upper nodes; male inflorescence a capitulum, peduncle 0.4-1.5 cm; glomerules few flowered, sometimes only 1 developing, bracts ovate-lanceolate, ca. 0.7 mm; female inflorescence a cluster of a few flowers; bracts ovate, 0.6 mm. Male flowers pedicellate, in bud ca. 1.8 mm; perianth lobes 4, obovate-oblong, connate 1/2 of length, subapically corniculate; stamens 4; rudimentary ovary oblong. Female perianth lobes unequal, largest lobe cymbiform, subapically corniculate. Achene ovoid, ca. 0.7 mm, compressed, smooth, enclosed by perianth lobes. Fl. May-Aug, fr. Aug-Oct.

Shaded moist places, rocks in forests; 200-1500 m. Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, E Sichuan, SW Zhejiang [Bhutan].