杜根藤 du gen teng

Gendarussa quadrifaria Nees in Wallich, Pl. Asiat. Rar. 3: 105. 1832; Adhatoda quadrifaria (Nees) Nees; A. zollingeriana Nees; Calophanoides quadrifaria (Nees) Ridley.

Herbs. Stems 4-angled, basally decumbent and usually rooting at nodes then erect, sulcate, bifariously pubescent, soon glabrescent. Petiole 0.4-2.5 cm, sparsely pubescent; leaf blade oblong, lanceolate, to rarely orbicular, (2-)6-8 × (1-)2-3.5 cm, both surfaces glabrous or only pubescent along veins, secondary veins 5-7 on each side of midvein, base narrowly cuneate and decurrent onto petiole, margin entire or slightly serrate, apex acute. Spikes axillary, ca. 1 cm, usually 3-flowered, solitary or several in a cluster; bracts with a 3-4 mm petiole, ovate to obovate, 3-8 × 3-5 mm, sparsely pubescent, pinnately veined, apex obtuse; bracteoles linear, ca. 1 mm, glabrous. Calyx 5-6 mm, outside puberulent, 5-lobed almost to base; lobes linear-lanceolate. Corolla white with purple spots on lower lip, ca. 8 mm, outside pubescent; lower lip ca. 4 × 3 mm, patent, apex 3-lobed; upper lip oblong, erect, apex 2-lobed. Anthers with thecae superposed, lower ones spurred at base. Ovary glabrous; style ca. 6 mm, sparsely hirsute. Capsule ca. 8 mm, glabrous. Seeds ovate in outline, ca. 1.5 × 1 mm, verruculose, glabrous.

On rock in forested valleys; 800-1600 m. Chongqing, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Sichuan, Yunnan [India, Indonesia, Laos, Myanmar, Thailand, Vietnam].