Pogostemon sampsonii (Hance) Press (1982: 74)

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

24. Pogostemon sampsonii (Hance) Press (1982: 74) . Dysophylla sampsonii Hance (1866: 234) . Eusteralis sampsonii (Hance) Panigrahi (1976: 478) . Lectotype (here designated): — CHINA. Guangdong: Guangzhou, “in udis circa Canthonem”, November 1864, G.T. Sampson in Herb. H.F. Hance 10946 (BM!, isolectotypes K!, NY!, P!). Figure 17 .

Dysophylla benthamiana Hance var. intermedia C.Y. Wu & S.J. Hsuan in Wu et al. (1965: 237). syn. nov. Dysophylla stellata (Lour.) Benth. var. intermedia (C.Y. Wu & S.J. Hsuan) C.Y. Wu & H.W. Li in Li (1975: 77). Type: — CHINA. Hainan: Yahsien (now Sanya), 1300 m, 25 February 1933, F.C. How & N.K. Chun 70209 (holotype IBSC!, isotype IBK!).

32 • Phytotaxa 200 (1) © 2015 Magnolia Press

DENG & GE

Annual herbs, 15–50 cm tall. Stems hollow, sub-terete or 4-angled, branched, erect-ascending, base procumbent and trailing at base, basal internodes short, glabrous, reddish, swollen at nodes. Leaves in whorls of 3–4, sessile; blade obovate-oblong to oblanceolate or linear-lanceolate, 1.5–7 cm × 3–8(–14) mm, papery, glabrous, densely black glandular, base attenuate, margin conspicuously serrate except basal 1/3 entire, apex obtuse to acute; midvein elevated abaxially, lateral vein obscure. Spike terminal, simple, 1.2–7 cm × 5–8 mm, continuous; flowers subsessile; rachis glandular villous. Bracts and bracteoles ovate, ovate-lanceolate, spathulate or linear, 1–1.7 mm long, reddish, margin ciliate. Calyx broadly campanulate, 1.4–1.7 mm long, 5-veined, pubescent and yellow glandular outside, purlish red; teeth 5, ovate-triangular, more than 1/3 as long as the calyx, pubescent inside, margin ciliate. Corolla purplish-red, 2–2.5 mm, exserted, subequally 4-lobed. Stamens 4, erect, much exserted;

POGOSTEMON ( LAMIACEAE )

Phytotaxa 200 (1) © 2015 Magnolia Press • 33 filament purplish red, inserted at a same height in the tube, 2.6–3 mm long, much exserted, bearded at middle, glabrous at the base, bearded portion exserted; anthers 1-locular, cell apex dehiscent; style purplish red, 3.5–4 mm long; stigma bifid, subequal or unequal, lobes ca. 0.5–1 mm long. Nutlets 4, ca. 0.7 × 0.5 mm, ovoid, dark brown, shiny.

Distribution and habitat:— The species is endemic in south China and occurs in Guangdong, Guangxi, Hainan, Hunan and Jiangxi ( Figure 16 ). It is common in marshy grounds, grass lands, beside rice paddies and at streamsides, at 30–1100 m elevation.

Phenology:— Flowering from September to October and fruiting from October to November.

Taxonomic notes:— The species is easily distinguished from other Chinese Pogostemon species by the stems being 4-angled, leaf blades obovate-oblong to oblanceolate or lanceolate, with the margin conspicucously serrate distally but entire toward the base.

Dysophylla stellata var. intermedia was reduced to synonymy of D. stellata (= Pogostemon stellata ) by Li & Hedge (1994). Examination of the type material revealed that it differs from P. stellata evidently by its 4-angled (not terete) stems, obovate-oblong to oblanceolate or lanceolate (not linear) leaf blades, with the margin conspicuously serrate distally but entire toward the base (not remote serrulate or entire), and the calyx to 2 mm long (not 1–1.1 mm long). However, these characters are well identical with P. sampsonii .

Figures

FIGURE 16. Distribution maps of Pogostemon linearis, P. pentagonus, P. sampsonii and P. stellatus.

FIGURE 17. A–I. Pogostemon sampsonii. A. Habit; B. Flower; C. Calyx; D. Calyx split; E. Corolla split open with stamens; F–I. Bracts and bracteoles. Drawn by Y.X. Liu based on G. Yao 273 (IBSC).