Pogostemon auricularius

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

15. Pogostemon auricularius (L.) Hasskarl (1843: 127). Mentha auricularia Linnaeus (1767: 81) . Dysophylla auricularia (L.) Blume (1826: 826). Mentha foetida Burman (1768: 126) , nom. illeg. superfl. Lectotype (designated by Tucker et al. 1980: 238): — SRI LANKA. Without locality, 1670–1677, Herb. Hermann 4:42, no. 411 (BM!). Figure 11 .

POGOSTEMON ( LAMIACEAE )

Phytotaxa 200 (1) © 2015 Magnolia Press • 23 Annual herbs, 0.4–2 m tall. Stem procumbent or diffuse basally, rooting at nodes, ascending, sometimes branched upwards, densely yellow spreadingly hirsute. Leaves opposite; petiole absent or rarely up to 1 cm in length; blade oblong to ovate-oblong, 2.5–8 × 1.5–3 cm, yellow strigose on both surfaces, with scattered impressed glands, base rounded to shallowly cordate, rarely cuneate, margin serrate, apex obtuse to acute, lateral veins 5–7 pairs on each 24 • Phytotaxa 200 (1) © 2015 Magnolia Press

DENG & GE side of the midvein, conspicuous abaxially. Spikes terminal, simple, 3–18 cm long, 6–10 mm wide, apex caudateacuminate, continuous or sometimes interrupted basally, strigose; peduncle subsessile to 2 cm long; flowers subsessile. Bracts and bracteoles ovate-lanceolate, narrowly elliptic, linear, or spatulate, 1.8–2.6 mm long, pubescent and brown glandular abaxially, glabrous adaxially, margin strigose. Calyx campanulate, ca. 1 mm long, 5-veined, glandular and with a few hairs outside, glabrous inside; teeth 5, triangular, ca. 1/3 as long as calyx tube, margin ciliate, incurved in fruit. Corolla white to purplish, ca. 2.3 mm long, much exserted, sparsely pubescent and glanular outside, subequally 4-lobed. Stamens 4, much exserted; filaments ca. 2.3 mm long, inserted at the middle of corolla tube, bearded portion exserted; anthers 1-locular, cell apex dehiscent; style ca. 3.8 mm long; stigma bifid, equal, lobes ca. 0.5 mm. Disc ca. 0.3 mm long. Nutlets 4, ca. 0.7 mm long, ellipsoid-fusiform, brown, reticulate.

Distribution and habitat:— Pogostemon auricularius is one of the most widespread species in the genus. It is distributed in Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, New Guinea, the Philippines, Sri Lanka, Thailand and Vietnam. In China, it occurs in Fujian, Hainan, Guangdong, Guangxi, Jiangxi, Taiwan and Yunnan provinces ( Figure 10 ). It grows in wet areas or marshy grounds in sparse forests, stream sides, or near villages, at an elevation of 200–1700 m.

Phenology:— Flowering and fruiting from April to December.

Taxonomic notes:— Pogostemon auricularius is similar to P. barbatus Bhatti & Ingrouille (1997: 109) in habit, but differs from the latter in its petioles being absent or less than 1 cm long (not usually 1–2 cm long), yellow strigose (not brown or dark brown strigose) stems and both leaf surfaces, the leaves with rounded to shallowly cordate to rarely cuneate (not broadly cuneate to cuneate) base and serrate (not crenate or double crenate) margin.

In the protologue of both Mentha auricularia and M. foetida , three same pre-1753 synonyms were included, i.e., “ Aloperuro-Veronica ” of Flora Zeylanica ( Linnaeus 1747) , “ Veronica hirsuta latifolia aquatica ” of Thesaurus Zeylanicus ( Burman 1737) and “ Majana foetida ” of Herbarium Amboinense ( Rumphius 1750). Linnaeus (1771) treated M. foetida as a synonym of M. auricularia . As discussed by Merill (1921), the species in Burman’s Flora Indica were often described by Linnaeus (1767, 1771) in his Mantissa Plantarum under the same name Burman used or under another name. Obviousely, these two names were based on the same material and the later Burman’s name M. foetida is thus an illegitimate superfluous name. Tucker et al. (1980) designated Herb. Hermann 4:42, no. 411 at BM as the lectotype of M. auricularia . According to the Article 7.5 of ICN ( McNeill et al. 2012), the type of M. foetida is the same as M. auricularia .

Figures

FIGURE 10. Distribution maps of Pogostemon fraternus, P. hispidocalyx, P. auricularius and P. barbatus.

FIGURE 11. Pogostemon auricularius. A. Habit; B. Bract; C. Flower; D. Calyx; E. Corolla and stamens; F. Ovary and style. Drawn by H.P. Yu based on C.L. Tso 21899 (IBSC) and provided by the Flora of Hong Kong project via Hong Kong Herbarium (HK)