Magnolia huongiana Q.N.Vu, 2025

Cao, Thi Viet Nga, Vu, Tien Chinh, Truong, Quang Cuong, Luu, The Trung & Vu, Quang Nam, 2025, Magnolia huongiana (M. sect. Michelia, Magnoliaceae), a new species from southern Vietnam, Phytotaxa 683 (2), pp. 165-170 : 166-170

Magnolia huongiana Q.N.Vu , sp. nov. ( Figs 1 –3)

TYPE:— VIETNAM. Lam Dong Province, Lac Duong District, Da Chais Commune ( Bidoup-Nui Ba National Park ), in montane evergreen broadleaf forests mixed with some gymnosperm species, 1506 m elev., 12º11 ’ 1 ’’ N, 108º41 ’ 31 ’’ E, 03 April 2024, Truong 030424 (holotype: VNF; isotypes: VNF, IBSC) .

Magnolia huongiana is most similar to M. braianensis but differs in its dense, ferruginous brown hairs on young twigs, petioles, terminal buds, brachyblasts vs. dense yellowish blonde hairs; stipular scar reaching apex of petiole vs. completely free from petioles; more numerous spathaceous bracts 2–3 (vs. 1), cylindrical fruits vs. obovoid to subglobose syncarpous fruits ( Table 1).

Evergreen trees, to 18 m tall and 35 cm dbh. Bark slightly fissured, gray outside and yellowish inside. Young twigs, petioles and elongate densely ferruginous brown hairs on terminal buds. Twigs slender, internodes 7–15 × 3–5 mm, dotted with small lenticels. Stipular scar reaching apex of petiole. Leaves evenly distributed, spirally arranged, ferruginous brown (especially on abaxial midrib) on both surfaces of young leaves, becoming glabrous, shiny on mature leaves; petioles 15.0–18.0 × 2.0 mm, 3.0–5.0 mm thickened towards the base; leaf blades elliptic, (8.0–)11.0– 15.0 × (2.5–)4.0–5.0 cm, base cuneate and gradually attenuate into petiole, apex acuminate to acute, acumen 0.3–0.5 cm long; midrib and secondary veins abaxially prominent, secondary veins 13–16 on each side of the midrib, meeting in intramarginal veins ca 0.3–0.5 cm from the entire margin, reticulate veins dense and abaxially prominent when dry. Brachyblasts with dense ferruginous brown hairs on abaxial surfaces, 0.5–1.0 × 0.3–0.4 cm long; spathaceous bracts 2–3. Flower buds broadly ovoid to ellipsoid, 1.0–1.5 × 0.5–0.8 cm, ferruginous brown hairs outside. Flowers axillary, solitary; tepals 12–15, subsimilar, oblanceolate, cream white to yellowish (sometimes light green), glabrous, 2.3–2.8 × 0.3–0.6 cm, tepals of inner whorls slightly smaller. Stamens ca. 34, subequal, creamy white, 0.8–1.0 cm long, glabrous; filament ca. 0.1 cm long; anthers laterally dehiscent; connectives produced into ca. 0.1–0.2 cm sharp appendages; scars of tepals and stamens 0.2 cm long, gynophore ca. 0.4 cm long. Gynoecium terete, 1.0–1.3 × 0.5 cm, ellipsoid, ca. 0.7 × 0.3 cm, protruding from androecium, carpels numerous, densely ferruginous brown hairy ellipsoid, ca. 2.0 × 1.0 mm, styles and stigmas ca. 1.8 mm long. Fruit cylindrical, the carpels becoming free at dehiscence, 7.0– 15 cm long (including scar and gynophore); follicles numerous, 1.0–2.2 × 1.0– 1.5 cm, globose to ellipsoid, glabrous in mature, small lenticellate. Seeds obovoid, ca. 1.0 × 1.0 mm, sarcotesta bright red, black color after removing the sarcotesta.

FIGURE 3. The distribution of Magnolia huongiana (•) in Lam Dong Province, Vietnam (upper left, made by Quang Nam Vu), in Bidoup Nui Ba National Park (lower right from Bidoup-Nui Ba National Park), and in the forest (lower, made by Quang Nam Vu from Google Earth).

Etymology:— In honor of Lê Văn HƯƠng, a former Director of the Bidoup-Nui Ba National Park, who has made many contributions to the conservation of biodiversity in the park.

Phenology:— Flowering March–May; fruiting August–November.

Distribution and habitat:— Distributed in southern Vietnam, Lam Dong Province, Lac Duong District, Da Chais Commune (Bidoup-Nui Ba National Park). It grows in montane evergreen broadleaf forests mixed with some gymnosperm species, associated with species such as Pinus dalatensis Ferré , P. krempfii Lecomte ( Pinaceae ), Dacrycarpus imbricatus (Blume) de Laub. ( Podocarpaceae ), Magnolia blaoensis (Gagnep.) Dandy , M. nitida W.W.Sm. ( Magnoliaceae ), Litsea sp. ( Lauraceae ), Pentaphylax euryoides Gardner & Champ. ( Pentaphylacaceae ), Rhodoleia sp. ( Hamamelidaceae ), and some species of Fagaceae and Ericaceae between 1500–1750 m elevation

Additional specimens examined:— VIETNAM. Lam Dong Province, Lac Duong District, Da Chais Commune ( Bidoup-Nui Ba National Park ), 1507.8 m elev., 12º11 ’ 1 ’’ N, 108º41 ’ 31 ’’ E, 28 Jul 2024, Vu 280724 (sterile) ( VNF) ; location at center between Hòn Giao ranger station and Giang Ly ranger station, 1750 m elev., 04 Oct 2024 (fr), Truong 041024 ( VNF) .

Conservation status:— Magnolia huongiana is known only from one locality, in Bidoup-Nui Ba National Park. There are no major threats to the species other than road access through the park and some tourism activities. No regenerating individuals have been observed. AOO (area of occupancy) is estimated less than 10 km 2 (criteria B2a). The number of mature individuals found is ca. 10 (less than 50, criteria D), so it is assessed here as CR B2a, D (critically endangered) according to the criteria of IUCN (2024). Research activities and a monitoring program are recommended to understand the reproductive biology of the species and the population trend. Moreover, in situ and ex situ conservation action should be designed for possible population reinforcement programs aimed at increasing the small number of individuals in the population.

Figures

FIGURE 1. Magnolia huongiana. A. Habitat of M. huongiana. B. Habit, with inset showing bark (lower left). C. Branch apex with adaxial view of leaves, stipular scar reaching apex of the dense ferruginous brown hairs on petiole, and multi-tepals of axillary, solitary flower. D. Flower with dense ferruginous brown hairs on brachyblast and green tepals. E. A view of one flower and scars of petioles. F. Gynoecium terete, protruding from androecium. G. Gynoecium with numerous carpels, the gynophore, and scars of tepals and stamens. H. Subsimilar tepals and stamens of a flower. I. A ripe fruit. J. Seeds.