Ilex decapetala Yi Yang, Nuraliev & W. Hu 2026, sp. nov.
Authors: Yang, Yi, Hu, Wan, Huang, Tao, Wang, Jing, Sinh Nguyen, Khang, Ban, Ninh Khac, Bui, Van Thanh, Xuan Dac, Le, Nuraliev, Maxim S.
Type: Taxonomic treatment
Published: 2026-08-03
Keywords: Biodiversity, Taxonomy, Plantae, Tracheophyta, Magnoliopsida, Fagales, Fagaceae, Ilex, Ilex decapetala

<p><i>Ilex decapetala</i> Yi Yang, Nuraliev & W. Hu sp. nov.</p><p>Figs 2, 3, 4</p><p><b>Type.</b></p><p>Vietnam • Quang Nam: Nam Giang District, Song Thanh Nature Reserve, forest, river bank, elev. 740 m a. s. l., 15°33'14"N, 107°24'24"E, 11 May 2019, <i>M. S. Nuraliev 2540</i> [(holotype MW! (MW 0756601, image available at https://www.gbif.org/occurrence/3004105330 and https://plant.depo.msu.ru/open/public/item/MW0756601); isotypes LBG! (LBG 00161813), MW! (MW 0756602, https://www.gbif.org/occurrence/3004115330 and https://plant.depo.msu.ru/open/public/item/MW0756602)].</p><p><b>Description.</b></p><p><i>Small trees or shrubs</i> about 4 m tall, most likely evergreen. <i>Branches</i> of the current year purplish or brown-purple, puberulent; second-year branches green, glabrescent; third-year and older branches greyish to brownish-grey, glabrescent. <i>Petioles</i> 6–10 mm long, green to purplish, puberulent, but glabrescent with age. <i>Leaf blades</i> lanceolate, elliptic, ovate-elliptic or obovate-elliptic, 3.7–8.5 cm long, 1.8–3.4 cm wide, chartaceous, both surfaces glabrous, sometimes sparsely puberulent along the mid-vein abaxially, secondary veins 7–11 pairs, base cuneate to obtuse, margin entire, apex acuminate to long acuminate. <i>Stipules</i> tiny, triangular to broadly triangular, dark brown, glabrous, base rounded, margin entire, apex acute, caducous. <i>Male inflorescences</i> and flowers unknown. <i>Female inflorescences</i> axillary, occurring on current-year and / or second-year branches, cymose, corymbiform, ca. 1.5–2 cm in diameter, with (1 –) 3–18 flowers per inflorescence (rarely a branch with several cymes resembling a thyrse due to development of bracts instead of foliage leaves); peduncles 5–14 mm long, puberulent; bracts tiny, triangular to broadly triangular, brown to dark brown; rachises of thyrse-like branches 2–4 cm long, puberulent. <i>Female flowers</i>: pedicel 4–9 mm long, puberulent; calyx ca. 2.5 mm in diameter, yellowish-green and scarious along margin, puberulent outside and glabrous inside, 6 - or 7 - lobed, lobes broadly deltoid and overlapping each other; corolla 4.5–6 mm in diameter when fully opened, tube ca. 1 mm long, lobes (8 –) 9–10 (– 11), elliptic, 1.8–2.1 mm long, 0.8–1 mm wide, pink to pink-violet, glabrous, rarely with sparse hairs along margin, apex rounded; staminodes 9–10 (– 11), usually in the same number as the petals, ca. 2 / 5 as long as the petals, glabrous, filaments pink, sterile anthers deltoid, pinkish-white; ovary superior, ca. 1.5 mm in height, subglobose or elliptic in top view due to the carpels arranged along a line, green, glabrous, with 9–10 locules, each locule 1 - ovuled; stigma elliptic-discoid, green, 9–10 - lobed. <i>Fruits</i> when young green, glabrous, with persistent puberulent calyx; ripe fruits unknown.</p><p><b>Etymology.</b></p><p>The species is named for its female flowers that mostly have 10 petals, which makes it distinct within the holly genus, because the flowers of <i>Ilex</i> are predominantly 4–7 - merous.</p><p><b>Phenology.</b></p><p><i>Ilex decapetala</i> starts to flower in April or May; fruiting season is unknown.</p><p><b>Distribution.</b></p><p><i>Ilex decapetala</i> is currently known from three neighbouring provinces of central Vietnam, i. e. Kon Tum, Quang Nam and Thua Thien Hue (Fig. 5). Two of the localities are within several km of the border with Laos, which means that the presence of the species in Laos is highly possible.</p><p><b>Preliminary conservation assessment.</b></p><p>DD (Data Deficient). Three populations were recorded, with the two most distant ones located 185 km apart from each other. Further field observations on the species and an assessment of the quality of its habitats are needed.</p><p><b>Paratypes.</b></p><p>Vietnam • Thua Thien Hue: A Luoi 4 Commune, A Roang 2 Village, remnants of primary evergreen broad-leaved forest on sandstone mountain, around point 16.145186°N, 107.416529°E, elev. 600–700 m a. s. l., 27 April 2026, <i>Ninh Khac Ban, Bui Van Thanh, Khang Sinh Nguyen et al. AL 603</i> (HN!); • ibid., 10 June 2026, <i>Ninh Khac Ban et al. AL 817</i> (HN!); • Kon Tum: Kon Plong District, Mang Canh Municipality, Thach Nham protected forest, 13 km NNE from Mang Den town, in the forest, river bank, elev. 1050 m a. s. l., 14°42'35"N, 108°19'00"E, 22 April 2015, <i>M. S. Nuraliev 1411</i> [MW! (MW 0750769, image available at https://www.gbif.org/occurrence/1697868135 and https://plant.depo.msu.ru/open/public/item/MW0750769)].</p>