Acorus shannai (Acoraceae), a new species from Southern China Author Cheng, Zhuo 0000-0001-7807-2571 Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission of China, Beijing 100081, China & College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China Author Liu, Xinyu https://orcid.org/0009-0007-6299-1283 Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission of China, Beijing 100081, China & College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China Author Yu, Nianting https://orcid.org/0009-0005-9469-6567 Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission of China, Beijing 100081, China & College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China Author Chen, Weizhe https://orcid.org/0009-0009-2600-9146 Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission of China, Beijing 100081, China & College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China Author Zhao, Haofeng https://orcid.org/0009-0009-9597-0600 Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission of China, Beijing 100081, China & College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China Author Li, Feifei 0000-0003-4733-6268 China National Botanical Garden (North Garden), Beijing 100081, China Author Long, Chunlin 0000-0002-6573-6049 Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission of China, Beijing 100081, China & College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China & Institute of National Security Studies, Minzu University of China, Beijing 100081, China text PhytoKeys 2025 2025-01-20 251 175 188 journal article 307720 10.3897/phytokeys.251.139141 3fcd63ea-e435-4380-82b7-f6113e562f91

Table 1. Comparative morphological traits of Acorus shannai, “ A. tatarinowii ”, and A. gramineus highlighting diagnostic features.

Characters	A. shannai	“ A. tatarinowii ”	A. gramineus
Whole plant	Leaves drooping	Leaves upright	Leaves upright
Rhizome	Dark green, 8–20 × 0.7–1.2 cm.	Green, 5–15 × 0.5–1 cm.	Dark green, 3–8 × 0.4–0.6 cm.
Leaf blade	Wide, 30–60 × 0.7–1.5 cm	Wide, 20–50 × 0.7–1.3 cm	Narrow, 20–30 × <0.7 cm
Sheath	Purple	Green	Green
Peduncle	8–25 cm	4–15 cm	2.5–9 (15) cm
Spadix	5–13 cm	(2.5) 4–6.5 (8.5) cm	3–9.5 cm
Spathe	10–41 cm	13–25 cm	3–9 (14) cm
The length ratio of spadix vs spathe	ca. 2–3 times	More than 3 times	ca. 1–3 times
Infructescence	Yellow	Green	Green
Fruit	Most of the fruits kept immature, fruit with distinct dorsal sutures	Most of the fruits were mature, fruit without distinct dorsal sutures	Most of the fruits were mature, fruit without distinct dorsal sutures
Smell	Strong fennel aroma	Aromatic	Aromatic
Habitat	Growing on mountain slopes with moist soil or brook banks; <1,500 m	Growing on rocks or rocky banks of brooks with fast-flowing water; alt. <2,600 m	Growing in forests or on stream banks; <1,800 m