Pogostemon formosanus Oliver (1896

YAO, GANG, DENG, YUN-FEI & GE, XUE-JUN, 2015, A Taxonomic Revision Of Pogostemon (Lamiaceae) From China, Phytotaxa 200 (1), pp. 448-450 : 448-450

6. Pogostemon formosanus Oliver (1896 : pl. 2440). Lectotype (here designated):— CHINA. Taiwan: “Formosa, Ape’s Hill, Takow”, no date, A. Henry 1178 (K!, isolectotypes CAL!, MO!, NY!, P!, PE!, US!).

Perennial herbs or subshrubs, to 1 m tall. Stems erect, terete or angular, branched, pubescent, glabrescent. Leaves opposite; petiole slender, to 4.5 cm long; blade rhombic-lanceolate to ovate or broadly ovate, 2.5–10 × 1.5–6 cm, papery or membranous, adaxially glabrous or sparsely strigulose, abaxially glabrous or minutely hairy on veins and inconspicuously glandular, base broadly cuneate to cuneate-attenuate, margins entire basally, irregularly incised toward apex or 3-lobed, apex acuminate; lateral veins 2–5 pairs on each side of the midvein. Spikes 2–8 cm long, 1–1.5 cm wide, terminal or axillary, continuous or sometimes interrupted basally, with more than two lateral branches; peduncle 1–3.5 cm long; cymes 5–8-flowered, peduncle short or sessile, flowers subsessile. Bracts and bracteoles linear-lanceolate to linear, 3–4 × 0.5–0.7 mm, subglabrous or sparsely pubescent along veins, margin slightly ciliate. Calyx subtubular, 4–4.4 mm long, 5-veined, glabrous or sparsely pubescent along veins and glandular outside, glabrous and glandular inside of tube; teeth 5, equal, narrowly triangular, 1.3–1.5 mm long, ca. 0.5 mm wide at base, glabrous inside, margin ciliate. Corolla white or purplish, ca. 5 mm long, slightly exserted, 2- lipped, upper lip 3-lobed, lower lip entire. Stamens 4, much exserted; filaments 2.5–3 mm long, inserted at a height of 2.4 mm in the tube, bearded at middle; anther 1-locular, cell apex dehiscent. Style ca. 6 mm long; stigma bifid, equal, ca. 0.5 mm long; disc ca. 0.3 mm long. Nutlets 4, 0.8–0.9 mm long, ellipsoid, reticulate-foveate, black or brown, shiny.

Distribution and habitat:— The species is endemic to China, occurring in Taiwan ( Figure 4 ). It grows usually in the semi-shady forests, trailsides or gravelly slopes, at the elevation of 0–1100 m.

Phenology:— Flowering and fruiting from September to the following April.

Taxonomic notes:— Pogostemon formosanus resembles P. xanthiiphyllus Wu & Huang in Wu et al. (1977: 744) in the character of the leaf margins incised towards the apex, but differs from the latter in its glabrescent stems and leaves (not densely minutely hispid), linear-lanceolate or linear bracts and bracteoles (not oblong-lanceolate to broadly lanceolate), and the subtubular calyx, glabrous or sparsely pubescent along veins outside (not campanulate, minutely hispid on veins).

In the protologue, Oliver cited two collections (Henry 70, Henry 1178) collected from Taiwan, China. Here we choose Henry 1178 at K as the lectotype .

12 • Phytotaxa 200 (1) © 2015 Magnolia Press

DENG & GE

Figures

FIGURE 4. Distribution maps of Pogostemon formosanus, P. glaber var. glaber, P. glaber var. tsingpingensis and P. latifolius.