Pogostemon monticola

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 : 61

Key to Pogostemon monticola and related species in Taiwan and southern China

1. Leaves incised to shallowly 3(5)-lobed; spikes broadly cylindrical, 10–20 mm wide, verticillasters with distinct axis and secund flowers .......................................................................................................................................................... Pogostemon formosanus

- Leaves unlobed; spikes narrowly cylindrical, 6–10 mm wide; verticillasters with obscure axis and subcapitate flowers................2

2. Leaves with 4–6 pairs of lateral veins; calyx 2–2.7 mm long; corolla 2–2.6 mm long, hardly exserted from calyx .......................... ................................................................................................................................................................. Pogostemon amaranthoides

- Leaves with 3–4 pairs of lateral veins; calyx 2.5–4.5 mm long; corolla 3.5–5.5 mm long, slightly to distinctly exserted from calyx ...................................................................................................................................................................................................3

3. Bracts and bracteoles broadly ovate, ovate, elliptic or ovate-lanceolate; filaments 4.5–5 mm long, with bearded portions distinctly exserted from corolla; styles 6–7 mm long ...................................................................................................... Pogostemon chinensis

- Bracts and bracteoles oblong-lanceolate, lanceolate or ovate-lanceolate; filaments 2–3.5 mm long, with bearded portions hardly exserted from corolla; styles 3–4.5 mm long ....................................................................................................................................4.

4. Stems strigose; leaves finely strigose adaxially; spikes up to 7 cm long; calyx teeth 0.8–1 mm long, ca. 1/3 as long as calyx tube. ......................................................................................................................................................................... Pogostemon monticola

- Stems sparsely strigillose and glabrescent; leaves sparsely strigillose or glabrous adaxially; spikes up to 13 cm long; calyx teeth 1.3–1.5 mm long, 1/2–1/3 as long as calyx tube ..................................................................................... Pogostemon septentrionalis