Magnolia tienii H. T. Truong, N. T. A. Minh & T. V. Tran. A. Twisted 2026, sp. nov.

Le résumé fourni par la source

Magnolia tienii H. T. Truong, N. T. A. Minh & T. V. Tran sp. nov. Figs 5, 6 Diagnosis. Magnolia tienii is morphologically most similar to M. praecalva and M. sinica but differs from M. praecalva by having paired terminal flowers per twig (vs. solitary flowers), peduncles with two nodes on the first flower and 3–4 nodes on the second flower (vs. 3–4 nodes), elliptic leaves (vs. elliptic-oblong or oblanceolate leaves), and 11 tepals (vs. nine tepals). Type. Vietnam • Lam Dong Province, Dam Rong District, Lomburr Mountain, 1370 m a. s. l. 12°05'3.00"N, 108°18'5.00"E, 12 June 2024, H. T. Truong, N. T. A. Minh, T. V. Tran Mag. 126 (holotype DLU!; isotype VNM!, VTN - Taynguyen Institute for Scientific Research!). Etymology. The new species is named in honor of Dr. Tran Van Tien for his contributions to Magnolia research. Description. Trees up to 20 m tall and up to 0.8 m diameter at breast height, glabrous throughout, with a straight bole. Bark pale brown to gray-brown, rugose to fissured. Old twigs brown, young twigs deep green, 4–6 mm in diameter. Stipules free from the petiole. Leaves spirally arranged; petiole 2–2.5 cm, without a stipular scar, base slightly enlarged; leaf blade elliptic, base gradually narrowly cuneate and decurrent on petiole, apex slightly-attenuate or obtuse, concave, and often emarginate, 9.5–10.5 × 3.0– 3.5 cm, leathery, abaxially pale green, adaxially deep green and glossy; midvein prominent on both surfaces, secondary veins 10–12 on each side of midvein, meeting in an intramarginal vein not close to the margin, reticulate veins sparse and prominent on both surfaces when dry. Peduncle 0.4–0.6 cm, stout, 1–2 nodes (first flower) and 3–4 nodes (second flower). Two flowers terminal on the twigs. Spathaceous bracts just next to tepals, green-brown, obovoid to ovoid, caducous, apex concave. Tepals 11, in three whorls, cream white, fragrant; three outer tepals oblong-spatulate, 4–4.5 × 1.2–1.5 cm, apex obtuse; eight middle and inner tepals obovate-spatulate, 3–3.5 × 1–1.2 cm, apex obtuse or acute. Stamens ca. 45; connective appendage acute, narrowly triangular; anthers dehiscent introrsely, 1.5–1.6 × 0.1–0.2 cm, base reddish. Gynoecium long ovoid, receptacle short, carpels attached at approximately the same height, entirely hidden within androecium; carpels 2–4; ovules 2–3 per carpel. Fruiting peduncles stout, glabrous, 1–1.2 × 0.4–0.6 cm thick. Fruits green-brown when mature, dark brown when dry, obovoid, base cuneate, apex globose, 5–8.5 × 3.5–6.5 cm; mature carpels narrowly long ellipsoid to obovoid-ellipsoid, 4.5–5.5 × 3.8–4.2 cm, thickly woody, dehiscing completely along ventral sutures, abaxially with coarse lenticels, splitting into 2–4 valves, late the carpels more separating from each other, in the center a columella persistent with the attached seeds. Scars of perianth and stamens a long receptacle under fruit 5–6 mm, concave. Seeds 1–3 per carpel. Phenology. The plants were found flowering from May to June and fruiting from June to July. Distribution and habitat. Magnolia tienii grows scattered in primary forest at elevations of 1,300–1,400 m a. s. l. on Lomburr Mountain, Dam Rong District, Lam Dong Province. In contrast, historical specimens of allied taxa collected from other regions occur at lower elevations, typically below 1,000 m a. s. l Preliminary conservation status. Magnolia tienii is currently known only from a single localized population on Lomburr Mountain (Dam Rong District, Lam Dong Province, Vietnam). An extensive field survey within the area revealed fewer than five mature individuals growing in primary forest, with an estimated area of occupancy (AOO) of less than 2 ha. Consequently, following the IUCN Red List Categories and Criteria (IUCN 2024), M. tienii is provisionally assessed here as Critically Endangered (CR D) because of its critically small population size (fewer than 50 mature individuals). Additional field investigations are strongly recommended to monitor this population and identify potential additional localities.

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