A new species of Saprosma (Rubiaceae) from Nui Chua National Park, South Central Vietnam Author Pham, Quoc Trong 0009-0004-6879-7535 Institute of Life Sciences, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, Xuan Hoa Ward, Ho Chi Minh City, Vietnam phamquoctrong117@gmail.com Author Tagane, Shuichiro 0000-0002-1974-7329 Kagoshima University Museum, Kagoshima University, 1 - 21 - 30, Korimoto, Kagoshima, 890 - 0065, Japan stagane29@gmail.com Author Souladeth, Phetlasy 0000-0001-8563-1773 Faculty of Forest Science, National University of Laos, Dongdok Campus, Xaythany District, Vientiane Capital, Lao PDR p.souladeth@nuol.edu.la Author Yamamoto, Takenori 0000-0002-5487-6652 Rural Regeneration Research Center, Yamagata University, 1 - 23 Wakaba-machi, Tsuruoka-shi, 997 - 8555, Japan t.yamamoto0624@gmail.com Author Yamazaki, Kaito 0000-0001-5652-2551 Japan Wildlife Research Center, 3 - 3 - 7 Kotobashi, Sumida-ku, Tokyo, 130 - 8606, Japan; Graduate School of Science and Engineering, Kagoshima University, 1 - 21 - 35 Korimoto, Kagoshima, 890 - 0065, Japan., 819 - 0065, Japan k.yamazakii0323@gmail.com Author Kongxaisavath, Deuanta 0009-0000-4559-0647 Faculty of Forest Science, National University of Laos, Dongdok Campus, Xaythany District, Vientiane Capital, Lao PDR deuantar66789@gmail.com Author Nguyen, Tran Vy 0000-0002-9560-2850 Institute of Life Sciences, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, Xuan Hoa Ward, Ho Chi Minh City, Vietnam vychim@gmail.com Author Nguyen, Quoc Bao 0000-0001-8172-8578 Institute of Life Sciences, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, Xuan Hoa Ward, Ho Chi Minh City, Vietnam quocbao.nguyen98@gmail.com Author Truong, Ba Vuong 0000-0003-3452-8455 Institute of Life Sciences, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, Xuan Hoa Ward, Ho Chi Minh City, Vietnam bavuong2019@yahoo.com Author Dang, Van-Son 0000-0001-8681-4141 Institute of Life Sciences, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, Xuan Hoa Ward, Ho Chi Minh City, Vietnam dvsonitb@gmail.com text Phytotaxa 2025 2025-11-12 728 2 213 219 https://doi.org/10.11646/phytotaxa.728.2.11 journal article 314185 10.11646/phytotaxa.728.2.11 a09e41d9-e58f-489f-b6d7-b67684e7caa0 1179-3163 18415955

TABLE 1. Comparison of Saprosma nuichuaensis with its morphologically closest species (Pitard 1924, Pham 2000, Chen et al. 2011).

Characters	S. nuichuaensis	S. annamensis	S. ternata
Branches	terete	terete	angled
Leaf arrangement	opposite	opposite	whorls of 3 or opposite
Leaf blade size (cm)	5–9.5 × 2–3.5	8–10.5 × 2–3.5	8–15 × 3–6.5
Number of secondary veins (pairs)	5–8	7–8	7–10
Petiole length (mm)	2–5.5	2	6–12
Stipule length (mm)	2–2.5	1.5–2	5–12
Peduncle length (mm)	10–45	10–20	10–40
Bract length (mm)	1–4	NA	1–5
Flowers	4-merous	5-merous	4- or 5-merous
Calyx tube length (mm)	1–2	2.5	1–2
Calyx lobe length (mm)	0.2–0.5	1	ca. 1
Corolla tube length (mm)	3–7	2.5	3–8
Corolla lobe length (mm)	2–3	2	3–4
Fruit size	7–10 mm long, 6 mm in diam.	NA	8–12 mm long, 7 in diam.
Seed surface	verrucose abaxially	NA	smooth abaxially