Pogostemon monticola T.C.Hsu, S.W.Chung, S.H.Liu & W.J.Huang, 2021

Liu, Shih-Hui, Hsu, Tian-Chuan, Huang, Wei-Jie & Chung, Shih-Wen, 2021, Pogostemon monticola (Lamiaceae; Lamioideae), a new species from Taiwan, Phytotaxa 507 (1), pp. 51-66 : 57-59

Pogostemon monticola T.C.Hsu, S.W.Chung, S.H.Liu & W.J.Huang , sp. nov. ( Figs. 1 , 3 )

Diagnosis: — Pogostemon monticola is closely allied to P. septentrionalis in both morphological appearance and molecular phylogenetic relationships. However, the new species could be distinguished in having strigose (vs. sparsely strigillose and glabrescent) stems, adaxially finely strigose (vs. glabrous or sparsely strigillose) leaves, generally shorter (1–7 vs. 3–13 cm) spikes, smaller calyx teeth (0.8–1 vs. 1.3–1.5 mm long and wide) and slightly shorter corolla, filaments and styles.

Type: — TAIWAN. Hsinchu County: Jianshih Township, Hsiakelo National Alley , 1350 m, 18 September 2020, S. W . Chung 14416 (holotype TAIF!, isotype HAST!)

Description: —Perennial, terrestrial herbs or subshrubs, 30–80(–120) cm tall. Stems erect, obscurely tetragonal, strigose, slightly swollen at nodes. Leaves opposite; petiole (0.5–) 1–4 cm long, sparsely strigillose; blade ovate to rhombic-ovate, (2–)4–12 × (1–) 1.8–6 cm, herbaceous, finely strigose adaxially, sparsely strigose on veins abaxially, glandular-punctate on both surfaces, base broadly cuneate to cuneate-attenuate, margin double serrate or double crenate-serrate, sometimes obscurely 3-lobed in larger leaves, apex acuminate, lateral veins 3 or 4 pairs on each side of the midvein, conspicuously elevated abaxially. Spikes (1–) 2–7 cm long, 7–10 mm wide, terminal and sometimes also axillary, continuous or basally interrupted, single or with 2–4(–8) branches; peduncle 0.5–3.5 cm long; verticillasters many-flowered, flowers sessile. Bracts and bracteoles oblong-lanceolate to lanceolate, 1–5 mm long, 0.3–1.1 mm wide, strigillose on both surfaces and along margin. Calyx infundibuliform, 2.5–3.5 mm long, 5-veined, glandular and sparsely strigillose abaxially, glandular abaxially; teeth 5, triangular, equal, 0.8–1 mm long and wide, ca. 1/3 as long as the calyx tube, sparsely hirsute abaxially, margin ciliate. Corolla white, 3.5–4 mm long, slightly exserted from calyx, glabrous adaxially, sparsely hirsute on lobes abaxially, margin sparsely ciliate, obscurely 2-lipped, upper lip 3-lobed, lobes apex obtuse, lower lip entire, apex acute. Stamens 4, erect, exserted; filaments 2–3 mm long, inserted at middle of corolla tube, whitish proximally, purple distally, bearded with purplish moniliform hairs in the middle, the bearded portions 0.5–1 mm long, situated around the mouth of corolla; anther 1-locular, cell apex dehiscent. Style 3–4 mm long; stigma bifid, equal, 0.5–0.7 mm long; disc ca. 0.5 mm long. Mericarps 4, spheric or obovoid, 0.9–1 mm long, black or dark brown.

Distribution and habitat: — Pogostemon monticola is endemic to Taiwan, where it is sporadically recorded around the central-western mountainous region between Hsinchu County and Kaohsiung City at elevations of 1200– 2100 m. Plants usually grow on semi-open slopes along trails and in gaps under primary broadleaved forests.

Phenology: —The flowering of Pogostemon monticola is observed from September to October and fruiting is from November to December.

Etymology: —The Latin epithet monticola means “inhabitant of mountains”, referring to its rather inland and higher-mountainous distribution among the congeneric species in Taiwan. Vernacular names, “ ※山ḦĖff ” & “montane Pogostemon ”, are also proposed.

Conservation status: — Pogostemon monticola is currently recorded from six localities between Hsinchu County and Kaohsiung City in Taiwan, with an estimation of 2200 km 2 EOO, 40 km 2 AOO and 2000 mature individuals. All known localities are low-disturbed forested area without apparent threat. We therefore evaluated it as Near Threatened [ NT D1 +2] based on the latest IUCN guidelines ( IUCN 2019) .

Additional specimens examined (paratypes): — TAIWAN. Hsinchu County: Jianshih Township, Hsiakelo National Alley, 1300–1500 m, 9 September 2011, T. C. Hsu 4605 ( TAIF!); Yanglao , 1200 m, 10 October 2010, P. F. Lu 20968 (TAIF-372376!) . Kaohsiung City: Namasia District, Xingwangling , 1500 m, 15 November 1940, T. Suzuki ST20884 (TAI-097028!) . Miaoli County: Nanzhuang Township, Mt. Niaotsui Alley , 17 December 2006, M. J. Jung y121703 (TAIF-273576!) . Nantou County: Sinyi Township, Chunda Forest Rd. , ca. 1390 m, 13 January 1993, M. S. Chen 10 (HAST-24083!); Lele Shelter to Tuikuan, 1700–2100 m, 14 December 2011, T. C. Hsu 5180 (TAIF-387771!; TAIF-387772!) . Taichung City: Heping District, Setuzankokei , 950 m, 25 October 1941, T. Suzuki ST21576 (TAI- 097021!) .

Figures

FIGURE 1. Pogostemon monticola T.C.Hsu, S.W.Chung, S.H.Liu & W.J.Huang.A–B. Habit. C. Stem. D–E. Leaf.F. Spike.G. Bracts and bracteoles. H. Flowers. I. Dissected calyx. J. Flowers with calyx removed. K. Corola and stamens. L. Pistils and ovaries. Photographed by Wie-Jie Huang (A) and Tian-Chuan Hsu (B–L) based on Chung 14416.

FIGURE 3. Pogostemon monticola T.C.Hsu, S.W.Chung, S.H.Liu & W.J.Huang. A. Habit. B. Leaf, adaxial surface. B’. Leaf, abaxial surface. C. Stem. D. Bract. D’. Bbracteole. E. Flower. F. Dissected calyx. G. Corola tube and stamens. H. Pistil and ovary. Drawn by Che- Wei Lin based on Chung 14416.