Pogostemon parviflorus Bentham (1830: 31)

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

9. Pogostemon parviflorus Bentham (1830: 31) . Lectotype (here designated): — BANGLADESH. Silhet Division: Silhet, 1831, N. Wallich 1531 (K-W!, isolectotypes G!, K!, P!). Figure 6 .

Pogostemon championii Prain (1908: 254) , syn. nov. Type: — CHINA. Hong Kong: Mount Parker , no date, J.G. Champion 339 (holotype K!).

Pernnial herbs or subshrubs, 30–60 cm tall. Stem erect, terete toward base, obscurely angular upward, slightly dilated at nodes, a few branched, strigose. Leaves opposite; petiole 1–4.5 cm long, strigose; blade ovate to ovate-lanceolate, 4–12 × 2–6.5 cm, papery or membranous, strigose on both surfaces, base broadly cuneate to cuneate, margin obscurely double crenate to double serrate, entire at base, apex acuminate, lateral vein 4 or 5 pairs on each side of the midvein. Spikes 0.7–3.5 × 0.8–1 cm, terminal and axillary, continuous, with more than two lateral branches; peduncle 0.5–2.5 cm long; verticillasters many-flowered, flowers sessile. Bracts and bracteoles ovate to ovate-lanceolate, 4–6 mm long, strigose and glandular abaxially. Calyx tubular-inflated, 4–4.2 mm long, 5-veined, strigose and densely golden glandular outside, sparsely strigillose inside at the upper part of tube; teeth 5, narrowly triangular, equal, 1.2–1.3 mm long, 0.5–0.6 mm wide at base, sparsely strigillose inside, ciliate. Corolla white, pink, or purplish, 4–5.5 mm long, exserted, 2-lipped, upper lip 3-lobed, lower lip entire. Stamens 4, erect, much exserted; filaments ca. 4.5 mm long, all inserted at a height of 2 mm in the tube, bearded at middle, bearded portion exserted; anther 1-locular, cell apex dehiscent. Style ca. 5 mm long; stigma bifid, lobes subequal, ca. 0.7 mm long. Disc 0.6–0.7 mm long. Nutlets 4, 0.75 × 0.6 mm long, oblong or subglobose, abaxially slightly flat, adaxially ribbed, black, shiny.

Distribution and habitat:— This species is distributed in Myanmar, Cambodia, China, India, and Vietnam. In China, it occurs in Guangdong, Hongkong and Yunnan ( Figure 7 ). It grows in mixed forests, ravine, or near villages.

Phenology:— Flowering from August to November and fruiting from October to December.

Taxonomic notes:— Pogostemon championii was described by Prain (1908) based on a specimen collected from Hongkong. It is notable that, however, this specimen from Hongkong was identified previously as P. parviflorus in the Flora Hongkongensis ( Bentham 1861) and later by Hooker (1885). In its original protologue, Prain compared P. championii with P. pubescens Bentham (1848: 152) , but not P. parviflorus . He noted that P. championii is similar to P. parviflorus in morphological characters, but didn’t give the differences from the latter. Since Prain, P. championii has been recognized as an endemic species from China for a long time (Wu et al. 1977, Wu & Huang 1977, Li & Hedge 1994, Bhatti & Ingrouille 1997). However, examination of the type material reveals that Pogostemon championii is conspecific to P. parviflorus . Pogostemon parviflorus can be distinguished from other Chinese Pogostemon species by the characters of an obscurely double crenate or very shallow serrate leaf margin, very short spikes to ca. 1.5–3.5 cm long, ovate-lanceolate bracts, longer than the calyx and imbricate over flowers in young spikes.

Bhatti & Ingrouille (1997) considered Pogostemon parviflorus to be a synonym of P. benghalensis ( Burman 1768: 128) Kuntze (1891: 529) , which was treated as a synonym of P. plectranthoides by most taxonomists ( Bentham 1848, Miquel 1856, Hooker 1885, Kuntze 1891). Bhatti & Ingrouille (1997) differentiated P. benghalensis from P. plectranthoides in having “a corolla with a narrower cylindrical tube and a verticillaster which is generally less crowded”. As Hooker (1885) indicated, however, P. parviflorus is different from P. plectranthoides ( P. benghalensis as its synonym) by its narrower bracts, slender spikes and the indumentum. Pogostemon plectranthoides is densely whitish pubescent, while P. parviflorus has a lax grayish strigose

16 • Phytotaxa 200 (1) © 2015 Magnolia Press

DENG & GE indumentum. He also pointed out that the shape of the leaf margin is variable in P. parviflorus . A double serrate to shallow double serrate leaf margin was observed in specimens from Yunnan (Tao & Li 40021, Yao 365, Expedition to Xishuangbanna 34496) and India (Pantling s.n., Anonymous 21531, 32420), while leaves with shallow double serrate to obscurely double crenate margins were observed in specimens from south Guangdong (Yue-78 Team 6319, Tsang 25959) and Hong Kong (Hu 12421). Additionally, Pogostemon parviflorus also can be distinguished from P. plectranthoides by its smaller flowers with the corolla 4–5.5 mm long (vs. up to 8 mm long), filaments ca. 4.5 mm long (vs. up to 8.6 mm long), and the style ca. 5 mm long (vs. ca. 10 mm long). Here we agree to treat P. parviflorus as an independent species separate from P. plectranthoides .

POGOSTEMON ( LAMIACEAE )

Phytotaxa 200 (1) © 2015 Magnolia Press • 17

Figures

FIGURE 6. Pogostemon parviflorus. A. Habit; B. Bract; C. Bracteole; D. Flower; E. Calyx; F. Corolla slipt shown stmens; G. ovary and style; H. Nutlet. Drawn by Li Zhimin based on S.Z. Zhang et al. SCAUF1124 (SZBG).

FIGURE 7. Distribution maps of Pogostemon parviflorus, P. septentrionalis, P. xanthiiphyllus and P. brachystachys.