Pogostemon falcatus (C.Y. Wu) C.Y. Wu & H.W. Li

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

17. Pogostemon falcatus (C.Y. Wu) C.Y. Wu & H.W. Li in Li (1975: 76). Dysophylla falcata C. Y. Wu in Wu et al. (1965: 237). Type: — CHINA. Yunnan: Cheli Xian (now Jinghong Shi), Nan-hsien-ho, 800 m, October 1936, C.W. Wang 79441 (holotype PE!, isotypes A!, IBSC!).

Herbs, 30–50 cm tall. Stems erect, terete, basally woody, densely appressed hirsute, apex densely gray hairy, slightly swollen at nodes, sometimes branched upwards. Leaves opposite or in whorls of 3; petiole subsessile to ca. 3 mm long, densely silky; blades linear to falcate, 4.5–7.5 cm × 4–7 mm, adaxially appressed silky, abaxially densely so along veins and glandular, base attenuate, margin remotely serrate except base 1/2 entire, apex acuminate, midvein elevated abaxially, lateral veins 3–5 pairs on each side of the midvein, conspicuous abaxially. Spikes terminal, 2–7.5 cm × 4–6.5 mm, black when dry, compact, subtended from the leaf axil; pedicel ca. 0.7 mm long, pilose. Bracts and bracteloes linear, equivalent or slightly longer than calyx, densely silky. Calyx 1.5–1.7 mm long, membranous, sparely pilose outside, teeth 5, ca. 0.4 mm long, narrowly triangular, pilose outside, glabrous inside, margin ciliate. Corolla red, black when dry, 1.7–2.1 mm long, exserted, subequally 4-lobed. Stamens 4, much exserted; filaments black when dry, sparsely hairy at middle, inserted at the middle of corolla tube; anthers 1- locular, cell apex dehiscent; style ca. 2.5 mm long; stigma bifid, lobes equal, ca. 0.7 mm long. Nutlet unknown.

Distribution and habitat:— The species is endemic to China and only known from the type locality, southern Yunnan ( Figure 13 ). It grows on rocks by streams, at an elevation of about 800 m.

Phenology:— Flowering in October.

Taxonomic notes:— Pogostemon falcatus can be easily distinguished from other Chinese Pogostemon species by its woody stem and falcate leaves. In its original description, it was indicated that the species has opposite leaves. However, after examining the types, we found that there was a short petiole or a conspicuous scar where the leaf had fallen off on some nodes with two leaves. So, this species has the leaves opposite or in whorls of 3. The similar case was also observed in Pogostemon quadrifolius (Bentham 1930: 30) Kuntze (1891: 530) , which was clustered in the clade of subgen. Dysophylla sect. Dysophlla in a cladistic analysis based on morphological characters of Pogostemon species ( Ingrouille & Bhatti 1998). Accordingly, P. falcatus is treated here as a member of sect. Dysophlla. Further studies on the phylogenetic position of the species with leaves opposite or in whorls of 3 are neccessary.

POGOSTEMON ( LAMIACEAE )

Figures

FIGURE 13. Distribution maps of Pogostemon falcatus, P. cruciatus, P. fauriei and P. henanensis.