Oreocharis sanglocii K.S.Nguyen, Aver., Nuraliev, L.Wu & C.W.Lin, 2025

Nguyen, Khang Sinh, Averyanov, Leonid V., Nguyen, Van Canh, Nuraliev, Maxim S., Lyskov, Dmitry F., Wen, Fang, Wu, Lei & Lin, Che Wei, 2025, Oreocharis sanglocii (Gesneriaceae), a new species from Hoang Lien Son Range, north-western Vietnam, Phytotaxa 715 (2), pp. 129-141 : 131-137

Oreocharis sanglocii K.S.Nguyen, Aver., Nuraliev, L.Wu & C.W.Lin , sp. nov. ( Figs. 1–4 )

Type: — VIETNAM. Lao Cai Province: Bat Xat District, Y Ty Commune, Phin Ho Village, south-western slope at the base of the Lao Than Mountain, around point 22.60264°N 103.66505°E, at elevation of 1300–1600 m a.s.l., 8 November 2024, Phu Xa Be, LC-BX 001 ( holotype: HN!, isotypes: HN!).

Diagnosis: — Oreocharis sanglocii differs from the morphologically closest O. blepharophylla mainly in leaf blade with 6–11 pairs of secondary veins, 3–20-flowered inflorescence, yellowish outer surface of corolla tube, pubescent stamen filaments, and free anthers. The new species also differs from the most similar yellow-flowered species, O. tsaii and O. zhenpingensis , in larger leaf blades (4–17 × 2–7 cm), elliptic to narrowly oblong-elliptic or oblong-obovate to narrowly ovate or oblanceolate leaf blade with attenuate to cuneate or decurrent base, 6–11 pairs of secondary veins, 3–20-flowered inflorescence, corolla with purple-maroon markings at throat, and glabrous style.

Description:—Plant perennial, herbaceous, acaulescent. Stem unbranched, stout, 7–21 mm long, 6–10 mm thick, with short internodes, bearing several brown more or less straight roots. Leaves 10–15 per stem, rosulate, spirally arranged, petiolate. Petioles almost semicircular in cross section (flattened adaxially), up to 8 cm long near the stem base, 1–3 cm long at apical part of stem, (1)1.5–4(6) mm in diameter at middle, densely to moderately spreading white or pale purplish-red pilose with hairs up to 4 mm (sometimes to 7 mm) long. Leaf blades somewhat fleshy in vivo, thin and chartaceous in sicco, elliptic to narrowly oblong-elliptic or oblong-obovate to narrowly ovate or oblanceolate, rarely falcate, more than 3 times longer than petiole, 4–17 × 2–7 cm (excluding much smaller leaves at stem apex), adaxially grassy green, pilose on median vein in the basal half and glabrous otherwise, abaxially pale green, white to purplish-red pilose (densely so on veins and sparsely between veins); base attenuate to cuneate, sometimes obliquely attenuate or decurrent onto petiole; apex obtuse to acute; margin sub-entire to repand or strongly undulate approaching serrate, sparsely pilose; venation pinnate, secondary veins (6)9–11 on each side of median vein, median vein and secondary veins flat or slightly impressed adaxially and conspicuously raised abaxially. Inflorescences (1)2–8(10) per stem, axillary, cymose, with (3)7–18(20) flowers. Peduncle 3.5–8 cm long, 1–1.5(2.5) mm in diameter, light green, moderately spreading pilose with white or pale purplish-red glandular hairs up to 1.5 mm long mixed with scattered to dense eglandular hairs up to 2.5 mm long. Bracts narrowly lanceolate to linear, those of the basal pair 3–6 × 1–1.8 mm, decreasing in size distally, pale green, glabrous adaxially, sparsely pilose abaxially, margin entire and sparsely ciliate. Pedicel 4–25 mm long, ca. 0.5–1 mm in diameter, light green, densely spreading pilose with long glandular hairs or in the same manner as peduncle. Calyx actinomorphic, pale green to whitish and sometimes purplish distally, equally 5-lobed, divided to base (sepals apparently free); lobes basally appressed to corolla and distally spreading, lanceolate to narrowly elliptic, 3–5.5 × 0.8–1.2 mm, apex acute, margin entire, outer (abaxial) surface and margin sparsely to moderately pilose with long purplish-red eglandular hairs ( ca. 1–2 mm long) and sometimes also with glandular hairs ( 0.5–1 mm long), inner (adaxial) surface glabrous. Corolla zygomorphic, widely open (lobes spreading), bilabiate, 1.8–2.5 cm long (up to 3 cm long being flattened), light yellow to white with yellowish tint, at throat and bases of lobes (adaxially) with purple-maroon markings (ranging from individual blotch of various shape on each petal to continuous belt), outside densely to moderately spreading white glandular pilose (more sparsely so towards petal apices; hairs 0.3–0.7 mm long), inside glabrous, margin of lobes glandular ciliate; tube narrow, straight, 12–19 mm long, 3–4 mm in diameter at base, gradually narrowing from base to throat, constricted at throat ( 2–2.5 mm in diameter); adaxial lip 2-lobed, divided nearly to base, lobes (5)6.5–8.5 × 3–5.5 mm; abaxial lip 3-lobed, divided nearly to base, lobes (8)10–14 × 5–6.5 mm, lateral lobes overlapped by central lobe; all 5 lobes oblong-obovate to oblong-elliptic, margin entire, apex rounded. Stamens 4, didynamous, appressed to abaxial side of corolla; filaments filiform, straight, white, sparsely glandular pubescent in distal half; filaments of posterior (adaxial) pair 4.5–7 mm long, attached at 4–5.5 mm above corolla base; filaments of anterior (abaxial) pair 4–5.5 mm long, attached at 5.5–7 mm above corolla base; anthers free and separated from each other, deeply included in corolla tube, oblong-ovate, dorsifixed, 1–1.3 mm long, yellow, glabrous, with parallel thecae, introrse, longitudinally dehiscent. Staminode 1 (adaxial), attached at ca. 2–3 mm above corolla base, cylindrical, 0.8–1.7 mm long, yellowish, glabrous, apex obscurely capitate. Disk annular, 1– 1.5 mm high, light yellow, glabrous, margin undulate to slightly lobed. Pistil 7–11 mm long, glabrous; ovary superior, cylindrical, 5–8 mm long, ca. 1 mm in diameter, pale yellow; style 1.5–2.3 mm long, ca. 0.5–0.7 mm in diameter, white; stigma deeply included in corolla tube and appressed to its adaxial side, obliquely peltate, ca. 1–1.5 mm in diameter, papillulate. Capsule narrowly fusiform to fusiform, with the widest part above middle, straight, 13–31 × ca. 3 mm, reddish-purple when mature, glabrous, loculicidal, with persistent style.

Additional specimens examined ( paratypes): — VIETNAM. Lao Cai Province: Bat Xat District, Bat Xat Nature Reserve, 4 km SSE of Y Ty Village , disturbed forest, near stream, moist vertical cliff, 22°37'18''N 103°37'26''E,elev. 1860 m, 20 October 2018, M. S. Nuraliev 2360 ( IBK IBK00470617 , MW MW0595865 , SING SING0400376 ) ; same location, 11 June 2019, M. S. Nuraliev 2695 ( HN, HUTB, IBK IBK00470618 , MW MW0595866 , SING SING0400377 ) ; same location, 3 November 2022, M. S. Nuraliev, D. F. Lyskov NUR 3715 ( MW MW0595867 , MW0595868 , MW0595869 ) ; Lao Cai Province: plant obtained in Bat Xat District (approximately at the type locality) by Ms. Phu Xa Be and cultivated in Lam Dong Province, Di Linh Town , by Mr. Loc Bao Sang , photos and herbarium prepared on 28 October 2024, L. Averyanov, V. C. Nguyen, T. Maisak, AL3425 ( LE LE01277900 , photos LE01255290 ) .

Etymology: —The species is named after Mr. Loc Bao Sang, a horticulturist who obtained its flowers under cultivation.

Vernacular name: —The Vietnamese name “nhạc ngựa Sang Lộc” is proposed here.

Distribution, ecology, and phenology: — Oreocharis sanglocii is currently only recorded from Bat Xat Nature Reserve (Bat Xat District, Lao Cai Province, north-western Vietnam). It inhabits shaded steep slopes of mountains composed by granite or shale and covered by evergreen broad-leaved or mixed forests at elevations of 1300–1860 m a.s.l.

The species grows on wet or moist steep soil slopes and vertical cliffs, often near waterfalls, in association with mosses and herbs including the characteristic lithophytes such as Carex sp. , Elatostema sp. , Selaginella sp. , Phyllagathis longicalcarata C.Hansen , Polygala saxicola Dunn , Polystichum sp. , and Shortia rotata Gaddy & Nuraliev.

Flowers were recorded from October to November, fruits were observed in November, expectedly persistent till February.

Conservation status: —The records of Oreocharis sanglocii cited here represent two subpopulations distant for about 5 km from each other. The authors’ extensive exploration of this and some other areas within Bat Xat Nature Reserve, as well as several other parts of the Hoang Lien Son Range including the Hoang Lien National Park, failed to find any other populations. Each of the two known subpopulations is situated only in several hundred meters from a paved road. The “ type ” population is located at the base of the southwest slope of Lao Than Mountain, whereas the other one inhabits a deep river valley close to a fish farm and local homestays. Each subpopulation is estimated to include less than 500 mature individuals.

Oreocharis sanglocii occurs in a remote mountainous area and has not been much exploited by collectors for ornamental purpose.At the same time, the entire forest area was severely disturbed in the past by various human activities including forest logging, buffalo grazing and cultivation of Lanxangia tsaoko (Crevost & Lemarié) M.F.Newman & Škorničk. Under these conditions, the steep slopes and rocky habitats act as local refuges of natural vegetation. The local flora seems also to face threats from the rapid increase of tourist hiking activity without appropriate management control of authorities, especially along the route to the Lao Than summit. Comprehensive field surveys across Bat Xat Nature Reserve and adjacent areas are required to evaluate the actual distribution range of O. sanglocii and estimate the threats. According to the IUCN Red List Categories and Criteria ( IUCN 2024), we provisionally assess the new species as Data Deficient (DD).

Taxonomic notes: —All the yellow-flowered species of Oreocharis were demonstrated to belong (along with a few purple-flowered species) to a monophyletic group defined by Möller et al. (2011) as clade IIc. This group is widespread in south-western China and Indochina and exhibits remarkable morphological variation, especially in the floral structure. At the same time, the group seems to be uniformly characterized by four fertile stamens ( Möller et al. 2011).

Among the yellow-flowered species, Oreocharis sanglocii is likely to be most similar to O. zhenpingensis J.M.Li, Ting Wang & Y.G.Zhang in Li et al. (2017: 292), especially in more or less elliptic leaf blade, several inflorescences per plant, light yellow corolla, narrow corolla tube constricted at throat, and more or less oblong corolla lobes. As demonstrated in Table 1, the new species is readily distinguished from the latter by its larger leaves (blade 4–17 × 2–7 vs. 2–6.5 × 1.5–4.6 cm), attenuate to cuneate, sometimes decurrent ( vs. rounded or broadly cuneate) base of leaf blade, 6–11 ( vs. 4–6) pairs of secondary veins, adaxial leaf surface pilose on median vein in the basal half and glabrous otherwise (vs. densely villous throughout), margin sub-entire to repand or strongly undulate (vs. distinctly crenate-serrate), inflorescence with up to 20 ( vs. 1–4) flowers, entire ( vs. dentate) calyx margin, presence ( vs. absence) of purple-maroon markings at corolla throat, stamen filaments longer ( 4–7 mm vs. 3–3.8 mm long) and glandular pubescent in distal half ( vs. entirely glabrous), anthers free and separated ( vs. coherent in pairs), glabrous ( vs. densely pubescent) ovary and style, and peltate ( vs. bilobed) stigma.

Then, Oreocharis sanglocii shares a remarkable set of features with O. tsaii Y.H.Tan & Jian W.Li in Tan et al. (2015: 188), namely the corolla tube distinctly constricted at throat, relatively large corolla lobes, pubescent stamen filaments, free, non-coherent anthers, and peltate stigma. The new species is distinguished from O. tsaii (see Table 1) by its larger leaves (blade 4–17 × 2–7 vs. 1.3–5.5 × 1.2–4 cm), leaf blade much longer than wide ( vs. slightly longer than wide to nearly orbicular) with attenuate to cuneate or decurrent ( vs. subcordate to cordate) base and more numerous secondary veins (6–11 vs. 4–5 pairs), adaxial leaf surface pilose on median vein in the basal half and glabrous otherwise ( vs. densely villous throughout), inflorescence with up to 20 ( vs. up to 5) flowers, corolla light yellow to almost white with purple-maroon markings at throat ( vs. uniformly dull yellow), and glabrous ( vs. glandular pubescent) style.

Furthermore, Oreocharis sanglocii is somewhat similar to O. jasminina S.J.Ling, F.Wen & M.X.Ren in Ling et al. (2020: 124) and O. yunnanensis Rossini & J.Freitas (2014: 180, a replacement name for O. glandulosa Y.H.Tan & J.W.Li in Tan et al. (2013: 30)). The new species differs from them both by its more or less elliptic to oblong ( vs. ovate to cordate) leaf blade with attenuate to cuneate, sometimes decurrent ( vs. cordate to rounded) base and 6–11 ( vs. 6–7) pairs of secondary veins, corolla light yellow to almost white with purple-maroon markings at throat ( vs. uniformly yellow), corolla tube constricted ( vs. widening) at throat, and oblong-obovate to oblong-elliptic ( vs. more or less ovate) corolla lobes.

In its leaf shape and floral structure, the new species also has some resemblance to the yellow-flowered Chinese endemics Oreocharis forrestii ( Diels 1912: 224) Skan (1917 : t. 8719) (see also Wang et al. 1998, Cai et al. 2019) and O. georgei Anthony (1934: 202) (see also Wang et al. 1998). However, it can be readily distinguished from them by its leaf margin, which is sub-entire to repand or strongly undulate ( vs. irregularly coarsely double dentate to serrate in O. forrestii , and crenate to dentate or serrate in O. georgei ), higher number of flowers per inflorescence (3–20 vs. 2–10 in O. forrestii and 1–6 in O. georgei ), larger corolla (1.8–2.5(3) cm long vs. 1.5–1.8 cm in O. forrestii and 1.4–1.9 cm in O. georgei ), and the presence of a dark purple spot at the corolla throat ( vs. absence in both species). A relevant comparison of the two species is additionally provided in the protologue of O. oriolus J.Hu & F.Wen (2023: 3) .

Among the species of Oreocharis that lack yellow hues in the corolla coloration, O. sanglocii shows remarkable similarity with O. blepharophylla W.H.Chen, H.Q.Nguyen & Y.M.Shui in Chen et al. (2017: 300) (see Table 1) endemic to Son La province of Vietnam, especially in the indumentum of long spreading white to purple hairs, variation of the shape of leaf blade from elliptic to obovate, corolla with lobes pale (whitish) adaxially and dark purple throat, and also in glabrous pistil. The new species differs, however, in leaf blade with 6–11 ( vs. 5 or 6) pairs of secondary veins, inflorescence with up to 20 ( vs. 1–4) flowers, yellowish ( vs. purple) outer surface of corolla tube, distally glandular pubescent ( vs. entirely glabrous) stamen filaments, and anthers free and separated ( vs. coherent in pairs).

Finally, Oreocharis sanglocii resembles the purple-flowered O. obliqua C.Y.Wu ex H.W. Li (1983: 6) in having narrow more or less tubular corolla constricted at throat, corolla lobes much longer than wide, and more or less elliptic leaf blades, but it is distinct from O. obliqua by its more or less symmetrical ( vs. asymmetrical, clearly falcate) leaf blades with sub-entire to repand or strongly undulate ( vs. serrate) margin, light yellow to almost white ( vs. purple) corolla with longer tube ( 12–19 mm vs. ca. 10 mm long), oblong-obovate to oblong-elliptic ( vs. linear-oblong) corolla lobes, and distally glandular pubescent ( vs. entirely glabrous) stamen filaments ( Li 1983, Wang et al. 1998, Tran et al. 2023).

Figures

FIGURE 1. Oreocharis sanglocii. A. Habit. B, B'. Portions of leaf, adaxial and abaxial surfaces. C. Inflorescence. D, D'. Bract, abaxial and adaxial surfaces. E, E'. Corolla, front and lateral views. F. Corolla longitudinally opened at adaxial side, showing stamens and staminode. G, G'. Stamens (anterior pair), side and front view. H, H'. Staminode, showing variation in size. I. Calyx and pistil, lateral view. J. Pistil and disk, side view. K. Cross section of ovary. L. Capsule, lateral view. Drawn from the type LC-BX 001 by C.W. Lin.

FIGURE 2. Oreocharis sanglocii. A–C. Flowering plants in natural habitat. D, E. Portions of leaf, adaxial and abaxial surfaces. F. Inflorescence. G. Portion of inflorescence, showing bracts. H. Corolla, front and lateral views. I. Pistil with calyx and disk, lateral view. J. Stamens (anterior pair) and staminode. K. Cross section of ovary. L. Corolla longitudinally opened at adaxial side. M. Dehisced capsule. Photos A–C by P.X. Be, D–M by K.S. Nguyen from LC-BX 001.

FIGURE 3. Oreocharis sanglocii. A, B. Plants in natural habitat. C. Inflorescences. Nuraliev, Lyskov NUR 3715 (A) and Nuraliev 2360 (B, C). Photos by M.S. Nuraliev.

FIGURE 4. Oreocharis sanglocii. A. Inflorescence, side view. B. Calyx, view from below. C. Flower, lateral view. D. Flower, view from abaxial side. E, F. Flower, oblique and front views. G. Longitudinally dissected flower. H. Stamens, disk and pistil, view from adaxial side. I. Stamens prior to anther dehiscence. J. Pistil and disk, lateral view. K. Mature capsule, lateral view. L. Dehisced capsule, adaxial view. Nuraliev, Lyskov NUR 3715 (A, C, F, G, I–L) and Nuraliev 2360 (B, D, E, H). Photos by M.S. Nuraliev.