taxonID	type	description	language	source
EB553E1FFFBBFF9F89EBFBBEFCF9FECC.taxon	description	(Figs. 1 – 3)	en	Tran, Thi Phuong Anh, Nguyen, Khang Sinh, Quang, Bui Hong, Bui, Van Thanh, Trung, Nguyen Thi, Binh, Tran Duc, Nguyen, Thi Thanh, Wu, Lei (2025): Mitreola sinhoensis (Loganiaceae), a new species from northwestern Vietnam. Phytotaxa 731 (1): 87-95, DOI: 10.11646/phytotaxa.731.1.7, URL: https://doi.org/10.11646/phytotaxa.731.1.7
EB553E1FFFBBFF9F89EBFBBEFCF9FECC.taxon	diagnosis	Diagnosis: — Mitreola sinhoensis is morphologically most similar to M. liuyanii C. Liu & M. Q. Han in Liu et al. (2022: 250), but differs by having leaf blade narrowly lanceolate to linear-lanceolate (vs. narrowly oblanceolate), attenuate (vs. acute to rounded) at apex; peduncles 0.7 – 2.5 cm (vs. up to 5 cm) long and pedicels 0.7 – 1 mm (vs. 1 – 8 mm) long, purple (vs. pale green), and puberulent (vs. villous); corolla lobes oblong, 1.9 – 2.4 × 0.9 – 1.3 mm (vs. ovate, 1.3 – 1.6 × 1.2 – 1.5 mm); stamens inserted at the lower one-third (vs. near the middle) of the corolla tube; anthers widely elliptic to subrounded, ca. 0.5 mm long (vs. broadly ovate, ca. 0.3 mm long); and capsules puberulent (vs. glabrous). Type: — VIETNAM. Lai Chau Province: Sin Ho Commune (formerly Sin Ho District, Sa De Phin Commune), remnants of primary evergreen board-leaved forest on steep slopes of limestone mountain, at vertical cliffs near mountain top, shaded and moist place, nearby a seasonal steep small stream, around point 22.29352 ° N, 103.21750 ° E, elev. 1650 m a. s. l., not common, 18 April 2025, T. P. A. Tran, K. S. Nguyen, V. T. Bui, B. H. Quang, N. T. Trung, T. D. Binh, T. T. Nguyen, LC-SH 003 (holotype: HN 000081514!, isotypes: HN 000081515!, HN 000081516!).	en	Tran, Thi Phuong Anh, Nguyen, Khang Sinh, Quang, Bui Hong, Bui, Van Thanh, Trung, Nguyen Thi, Binh, Tran Duc, Nguyen, Thi Thanh, Wu, Lei (2025): Mitreola sinhoensis (Loganiaceae), a new species from northwestern Vietnam. Phytotaxa 731 (1): 87-95, DOI: 10.11646/phytotaxa.731.1.7, URL: https://doi.org/10.11646/phytotaxa.731.1.7
EB553E1FFFBBFF9F89EBFBBEFCF9FECC.taxon	description	Description: — Herb terrestrial or lithophytic, perennial, up to 15 cm high. Root several, fibrous, including 1 – 3 well-developed roots (distinct from the others) up to 8 cm long and 1 – 1.5 mm in diameter; additionally, 1 – 3 adventitious roots arising from each node of the basal internodes. Stem proximally prostrate, terminally erect to suberect, terete, (0.8 –) 1 – 1.8 (– 2) mm in diameter, usually branched several times, (3 –) 4 – 7 (– 10) cm long, rarely unbranched and 1 – 2 cm long, sparsely pubescent when young, glabrescent with age, pale green to dark purple; internodes (2 –) 4 – 8 (– 12) mm long; nodes slightly swollen in old stems. Leaves decussate, clustered on short distal portions of branches, pubescent on both surfaces as well as petiole and veins, trichomes short, white, ca. 0.2 mm long; petiole (2.5 –) 3 – 4.5 (– 5) mm long, 0.7 – 1 mm wide, almost flattened adaxially, sparsely to moderately pubescent, greenish; leaf blade chartaceous in sicco, narrowly lanceolate to linear-lanceolate, (2.5 –) 3 – 4 (4.5) cm long, (3 –) 4 – 5 (– 6) mm wide, adaxially dark green and densely pubescent, abaxially grayish-green and sparsely pubescent; base and apex attenuate; margin entire, somewhat shallowly undulate; midrib more or less flattened adaxially, slightly prominent abaxially; lateral veins brochidodromous, obscure, 5 – 7 on each side, inconspicuous adaxially and visible abaxially; tertiary veinlets invisible. Stipules interpetiolar, minute, inconspicuous, broadly triangular or scale-like, ca. 0.4 mm wide, papillate. Cymes usually 4 – 15 (rarely 1 – 3) per plant, terminal, erect, pedunculate, with 2 orders of dichasial branching (then with 7 flowers) or occasionally with 3 orders; peduncle terete, almost straight, (0.7 –) 1.2 – 2.2 (– 2.5) cm long, 0.6 – 1 mm in diameter, dark purple, occasionally purplish pale green, sparsely puberulent with spreading white hairs; inflorescence axes similar in shape and surface to the peduncle but shorter and thinner, (3 –) 4 – 7 (– 8) mm long, 0.3 – 0.5 mm in diameter. Bracts adpressed to inflorescence axes, narrowly triangular, dorsally thickened, broadly acute at apex, margin entire, abaxially purple to dark purple, sometimes with a pale green longitudinal center, adaxially glabrous, abaxially sparsely puberulent, basal ones the largest (3 – 4 mm long and 0.6 – 0.8 mm wide at base), gradually becoming smaller and shorter upwards. Pedicels terete, 0.7 – 1 mm long, sparsely puberulent to glabrescent, minutely wrinkled and densely papillate, each subtended by a purple subulate bract ca. 0.7 mm long. Flowers actinomorphic, pentamerous except for the gynoecium, ca. 5 mm across when fully open. Calyx broadly cupuliform, adpressed to the base of the corolla, divided nearly to base; lobes broadly triangular, 1 – 1.2 mm long, 0.5 – 0.6 mm wide at base, thickened dorsally, abaxially purple, sometimes tinged pale green along the keel, minutely papillate, abaxially purplish, both surfaces glabrous; apex acute to subacute; margin nearly entire or slightly irregularly undulate. Corolla sympetalous, outside hairless, minutely papillate or scurfy; a ring of dense, translucent, multicellular hairs present at corolla throat (i. e. at the border of tube and free lobes), with hairs ca. 0.6 mm long, spreading horizontally to slightly ascending and completely covering the orifice; tube urceolate, 1.4 – 1.6 × 1.6 – 1.8 mm, sparsely puberulous on the inner upper half with translucent, multicellular hairs, white to white flushed with purplish patches, with the lower half somewhat translucent; lobes horizontally spreading to slightly recurved at anthesis, oblong, 1.9 – 2.4 × 0.9 – 1.3 mm, adaxially minute papillate, entirely white or bluish white, sometimes tinged with pale lilac, acute at apex, margin entire. Stamens included within corolla tube, glabrous; filaments inserted at the lower one-third of the tube, erect (nearly parallel to the style), subterete, tapering upwards and slightly incurved at apex, 0.6 – 0.7 mm long; anthers 2 - locular, dorsifixed, introrse, surrounding the stigma, widely elliptic to subrounded, ca. 0.5 × 0.6 mm, bright yellow, rounded at apex, broadly cordate at base, dehiscing by two longitudinal slits. Gynoecium glossy, pale green or greenish white, glabrous; ovary superior, broadly conical, 0.8 – 0.9 mm wide at base, ca. 0.5 mm high, 2 - locular, rarely 3 - locular; ovules numerous in each locule, with axile placentation; styles 2 (– 3), almost completely connate, erect, 0.5 – 0.6 mm long, ca. 0.3 mm wide at base; stigma capitate to subglobose, 0.25 – 0.3 mm in diameter, minutely tuberculate. Capsule (immature or nearly mature) laterally compressed, distally bilobed for more than half to two-thirds of its total length, forming a V-shaped outline with a deep apical sinus at a divergent angle of ca. 90 o between two straight lobes, 3.2 – 3.7 mm long, 1 – 1.3 mm in diameter at the free lobes, green, often flushed with purple apically, sparsely puberulent, apex of free lobe mucronate to beaked. Seeds (nearly mature) numerous per capsule lobe, subglobose, ca. 0.3 mm in diameter, glabrous, minutely verrucate.	en	Tran, Thi Phuong Anh, Nguyen, Khang Sinh, Quang, Bui Hong, Bui, Van Thanh, Trung, Nguyen Thi, Binh, Tran Duc, Nguyen, Thi Thanh, Wu, Lei (2025): Mitreola sinhoensis (Loganiaceae), a new species from northwestern Vietnam. Phytotaxa 731 (1): 87-95, DOI: 10.11646/phytotaxa.731.1.7, URL: https://doi.org/10.11646/phytotaxa.731.1.7
EB553E1FFFBBFF9F89EBFBBEFCF9FECC.taxon	etymology	Etymology: — The specific epithet refers to the type locality, Sin Ho Commune in Lai Chau Province, Vietnam. Vernacular name: — The genus Mitreola is known in Vietnamese as “ Ti ểu m ạo ” (Pham 2003); accordingly, the new species is referred to “ Ti ểu m ạo sìn h ồ ”. Phenology: — Flowering is expected to last for around one month, with numerous open flowers and buds observed in mid-April. Immature and nearly ripen fruits were observed in April.	en	Tran, Thi Phuong Anh, Nguyen, Khang Sinh, Quang, Bui Hong, Bui, Van Thanh, Trung, Nguyen Thi, Binh, Tran Duc, Nguyen, Thi Thanh, Wu, Lei (2025): Mitreola sinhoensis (Loganiaceae), a new species from northwestern Vietnam. Phytotaxa 731 (1): 87-95, DOI: 10.11646/phytotaxa.731.1.7, URL: https://doi.org/10.11646/phytotaxa.731.1.7
EB553E1FFFBBFF9F89EBFBBEFCF9FECC.taxon	distribution	Distribution and habitat: — Mitreola sinhoensis has only been observed at its type locality in Sin Ho Commune, Lai Chau Province, northwestern Vietnam. It grows in shaded and moist areas with a thin soil layer or on rocks at bases of vertical cliffs near the mountain top, nearby a small seasonal steep stream and / or a small waterfall, at an elevation of 1650 m a. s. l., in remnants of primary evergreen broad-leaved forest on limestone. Mitreola sinhoensis co-occurs with the other herbaceous plants including Paraboea nutans D. Fang & D. H. Qin, Petrocosmea sp. (Gesneriaceae), Parnassia sp. (Celastraceae), Primula sp. (Primulaceae), Pternopetalum sp. (Apiaceae), and Valeriana jatamansi W. Jones (Caprifoliaceae). Proposed IUCN conservation status: — A single population of Mitreola sinhoensis has been documented, consisting of fewer than 50 mature individuals. Its representatives have been observed growing on vertical cliffs of steep limestone slopes. The habitat appears to be relatively undisturbed due to its inaccessibility and remoteness, limiting potential threats from human activity. Further field surveys in other limestone-reach areas, such as the current communes of Sin Ho (regions of former communes: Ta Phin, Sa De Phin), Tua Sin Chai (former communes of Ta Ngao, Tua Sin Chai) and Hong Thu (currently including former communes of Phin Ho, Ma Quai, Hong Thu), are recommended to better evaluate the species distribution and population size. Based on current data, the species is assessed as Data Deficient (DD) according to IUCN guidelines (IUCN 2024). Taxonomic relationships: — Among the currently known Mitreola species, M. sinhoensis shares morphological characters with the group characterized by conspicuously elongated stems bearing opposite leaves arranged along the stem or concentrated at the apex. To date, 17 species of this group have been reported worldwide, with the highest diversity (14 species) recorded in China (Tirel 1972, Leeuwenberg 1974, Nelson 1980, Li 1979, Fang et al. 1995, Conn 1996, Conn & Brown 1996, Li & Leeuwenberg 1996, Ma et al. 2010, Shan et al. 2019, 2021, You et al. 2020, Liao & Chen 2021, Liu et al. 2022, 2023, Hu et al. 2023, Nuraliev et al. 2023, Tran et al. 2024). Within this group, Mitreola sinhoensis most closely resembles M. liuyanii in sharing a small habit with branched, proximally prostrate stems, narrow leaves not exceeding 1 cm in width, and terminal several-flowered cymes. However, the former differs from the latter by its fibrous root system comprising several roots, including 1 – 3 well-developed roots up to 8 cm long and 1 – 1.5 mm in diameter, distinct from the others (vs. numerous roots of similar appearance), narrowly lanceolate to linear-lanceolate (vs. narrowly oblanceolate) leaf blades, widely elliptic to subrounded (vs. broadly ovate) anthers, and puberulent (vs. glabrous) capsules. It should be noted that, although the corolla tube of M. liuyanii was described as glabrous in the protologue, Figure 1 - H (Liu et al. 2022) illustrates sparse puberulent hairs on the inner upper half. Additional diagnostic characters of these two species are presented in Table 1.	en	Tran, Thi Phuong Anh, Nguyen, Khang Sinh, Quang, Bui Hong, Bui, Van Thanh, Trung, Nguyen Thi, Binh, Tran Duc, Nguyen, Thi Thanh, Wu, Lei (2025): Mitreola sinhoensis (Loganiaceae), a new species from northwestern Vietnam. Phytotaxa 731 (1): 87-95, DOI: 10.11646/phytotaxa.731.1.7, URL: https://doi.org/10.11646/phytotaxa.731.1.7
