透骨草 tou gu cao

Phryma leptostachya var. asiatica H. Hara, Enum. Sperm. Jap. 1: 297. 1948; P. asiatica (H. Hara) O. Degener & I. Degener; P. esquirolii H. Léveillé; P. humilis Koidzumi; P. leptostachya var. humilis (Koidzumi) H. Hara; P. leptostachya var. melanostachya Kitagawa; P. leptostachya var. nana (Koidzumi) H. Hara; P. leptostachya var. oblongifolia (Koidzumi) Honda; P. nana Koidzumi; P. oblongifolia Koidzumi.

Herbs, perennial, (10-)30-80(-100) cm tall. Stems simple or sometimes with apical branches bearing inflorescences, erect, 4-angular, apically pubescent or rarely subglabrous. Leaves petiolate or sometimes apical ones sessile; petiole to 4 cm, puberulent; leaf blade ovate-oblong, ovate-lanceolate, ovate-elliptic, ovate-triangular, or broadly ovate, 1-16 × 1-8 cm, herbaceous, both surfaces puberulent and sometimes more densely so along veins, secondary veins 4-6 on each side of midvein, base cuneate, rounded, or truncate but often decurrent for middle and basal leaves, margin serrate, dentate, or crenulate, apex acuminate, acute, or rarely subrounded. Spikes terminal or axillary, puberulent; peduncle 3-20 cm; inflorescence axis 10-30 cm; bracts subulate to linear, 1-2.5 mm. Pedicel short, erect at anthesis but later reflexed; bracteoles 2, at base of pedicel, subulate to linear, 0.5-2 mm. Calyx tubular, 5-ribbed, puberulent outside; tube 2.5-3.2 mm at anthesis; abaxial teeth 2, triangular, ca. 0.3 mm; adaxial teeth 3, subulate, 1.2-2.3 mm, apex ± hooked. Corolla light purplish, pale red, to white, tubular-funnelform, 6.5-7.5 mm, glabrous outside; tube 4-4.5 mm, ca. 1.5 mm broad at mouth, inside anteriorly puberulent; limb 2-lipped; abaxial lip 2.5-3 mm, apex 3-lobed with central lobe larger; adaxial lip erect, 1.3-2 mm, apex 2-lobed. Stamens inserted in corolla tube 2.5-3 mm from base, glabrous; filaments filiform, 1.5-1.8 mm, anterior 2 longer; anthers reniform-spherical, 0.3-0.4 × ca. 0.5 mm. Gynoecium glabrous; ovary obliquely oblong-lanceolate, 1.9-2.2 mm; style 3-3.5 mm; stigma 2-lipped, basal lip longer and oblong. Achene long ellipsoid, enveloped in persistent clavate calyx; persistent calyx tube 4.5-6 mm. Fl. Jun-Oct, fr. Aug-Dec.

Moist ravines, forests, roadsides, mountain slopes, hillsides; 300-2800 m. Anhui, Chongqing, Fujian, S Gansu, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xizang (Bomi, Gyirong), Yunnan, Zhejiang [Bhutan, N India, Japan, Kashmir, Korea, Nepal, N Pakistan, Russia (Far East), N Vietnam].

Phryma leptostachya subsp. leptostachya occurs in North America, from SE Canada to SE United States, W to South Dakota. The two intercontinental subspecies are morphologically highly similar, with the North American typical subspecies different in general from subsp. asiatica by having calyx tube 2-2.2 mm, adaxial calyx teeth nearly as long as calyx tube at anthesis, and adaxial corolla lip entire or emarginate. Yet they are genetically highly distinct (Z. Nie et al., Amer. J. Bot. 93: 1343-1356. 2005).