taxonID	type	description	language	source
03DB87E7FFF8FFF6CBACFE22FAD6FF48.taxon	materials_examined	TYPE: — VIETNAM. Quang Tri Province: Vinh Linh District, Hien Thanh Commune, in secondary forests, 17 ° 03 ′ 35.03 ′′ N, 107 ° 04 ′ 23.02 ′′ E, 50 m elevation, 19 November 2022, Le Tuan Anh & Van-Son Dang LTA 001 (holotype VNM [VNM 00070334!]; isotypes VNMN!, VNM [VNM 00070775!]).	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFF8FFF6CBACFE22FAD6FF48.taxon	diagnosis	Diagnosis: — Lasianthus trongii is closely related to L. tamdaoensis V. S. Dang in Dang & Naiki (2019: 51) in the shape of the leaves and inflorescence with long peduncle, but it can be distinguished from latter by its branches glabrous (vs. densely appressed pubescent to strigose), petioles 2 – 3 mm long (vs. 3 – 5 mm long), calyx 4 - lobed (vs. 5 - lobed), corolla tube 4 – 4.5 mm long (vs. 5 – 6 mm long), lobes 1 – 1.2 mm long (vs. 2 – 4 mm long), fruits reddish-orange (vs. blue), and pyrenes 4 (vs. 5). Shrubs 1 – 3 m tall; branches ca. 2 mm in diam., glabrous; internodes 2 – 4 cm long. Leaves opposite; blades lanceolateelliptic or lanceolate, 8 – 12 × 2 – 3 cm, subcoriaceous, glabrous on both surfaces, apex caudate-acuminate, 1 – 1.5 mm long, base subrotund, margin entire, midrib flat adaxially, prominent abaxially, secondary veins 6 – 8 pairs, ascending at the angle of 40 – 50 ° from the midrib, curved to the margin, prominent abaxially, tertiary veins parallel, faint adaxially, prominent abaxially; petioles 2 – 3 mm long, glabrous. Stipules small, narrowly triangular, 0.8 – 1 mm long, sparsely strigose at the base only. Inflorescences cymose, up to 7 - flowered; peduncles 2 – 3.5 cm long, sparsely strigose. Bracts persistent, linear to lanceolate, 1 – 2 mm long, pubescent. Flowers subsessile. Calyx campanulate to obconical, glabrous, tube 1.7 – 2.5 mm long, pale-green in vivo, lobes 4, triangular, 0.5 – 1 mm long, sparsely strigose toward apex, apex acute. Corolla cylindrical, tube 4 – 4.5 mm long, white, puberulent outside on the upper part, lobes 4, oblong-triangular, 1 – 1.2 mm long, pubescent outside, villous inside. Stamens 4, inserted at corolla tube; filaments 0.7 – 0.9 mm long, basally connate to corolla; anthers oblong, 0.3 – 0.5 mm long. Ovary 4 - locular; style 1.5 – 2 mm long, pubescent; stigma 0.3 – 0.5 mm long, 3 - lobed. Drupes ovoid to subglobose, 1.0 – 1.2 cm long, ca. 1.0 cm in diam., glabrous, reddish-orange when ripe; pyrenes 4. Seeds ovoid, 6 – 7 mm long, ridged on the abaxial face, blackish brown when dry.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFF8FFF6CBACFE22FAD6FF48.taxon	distribution	Distribution, habitat and phenology: — Lasianthus trongii is currently only known from Vietnam, occurring in provinces of Quang Binh and Quang Tri. It was found in secondary forests at elevation of 50 – 100 m. Flowering and fruiting specimens were collected in November and December.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFF8FFF6CBACFE22FAD6FF48.taxon	etymology	Etymology: — The new species is named in honor of Mr. Nguyen Dinh Trong who has made great contributions to local forest protection of the type locality in Quang Tri Province. Vernacular name: — Xú hƯƠng tr ọng (Vietnamese). Preliminary conservation assessment: — Lasianthus trongii is currently known from two localities in Quang Binh and Quang Tri Provinces, Central Vietnam. The Extent of Occurrence (EOO) is estimated less than 1,000 km 2 and the known Area of Occupancy (AOO) is 8 km 2. Two populations in Quang Tri and one population in Quang Binh were found in the understory of the broad-leaved evergreen forests, and each with 50 individuals were observed. In the population of Quang Tri, threats such as deforestation for charcoal and agricultural purposes have been observed, while the population in Quang Tri is inside the protected area of the national park and well-preserved. According to IUCN criteria B 1 a, b (iii), B 2 a, b (iii) and D, the species was assessed as Endangered (EN) (IUCN 2024).	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFF8FFF6CBACFE22FAD6FF48.taxon	materials_examined	Additional specimens examined (paratypes): — VIETNAM. Quang Binh Province: Phong Nha-Ke Bang National Park, Phong Nhar Botanic Garden, in broad-leaved evergreen forest, 17.55657 ° N, 106.29983 ° E, 89 m elevation, 5 December 2024, S. Tagane, V. S. Dang, P. Souladeth, Q. T. Pham, T. Yamamoto, T. Fujiwara, R. Masuda, K. Souvannakhoummane, K. Phengmala N 934 (FOF, KAG [KAG 189037], VNM). Notes: — It resembles L. tamdaoensis V. S. Dang in Dang & Naiki (2019: 51) which is known from Tam Dao National Park and Ba Vi National Park of northern Vietnam, but differs from that species in the several characters. This new species is also similar to L. kailarsenii Poopath, Vajrodaya & Napiroon in Napiroon et al. (2018: 208), a Thai species, but distinguished by its leaves 8 – 12 cm long (vs. 5 – 7 cm long), petioles 2 – 3 mm long (vs. 1 mm long), corolla tube 4 – 4.5 mm long (vs. tube 8 – 10 mm long), and fruits reddish-orange, ca. 10 mm in diam. (vs. blue, 3.5 – 5 mm in diam.). The comparison among Lasianthus trongii, L. tamdaoensis and L. kailarsenii is shown in Table 1.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFDFFF5CBACFBEDFF11FD18.taxon	materials_examined	TYPE: — VIETNAM. Hoa Binh Province: Da Bac District, Phu Canh Nature Reserve, in evergreen broadleaf forests, 20 ° 55 ′ 08.00 ″ N, 105 ° 01 ′ 40.00 ″ E ,, 1114 m elevation, 26 October 2021, T. S. Hoang, H. T. Nguyen, T. L. Ho & V. S. Dang HTS 4215 (holotype VNM [VNM 00070335!]; isotypes VAFS!, VNM [VNM 00070776!]).	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFDFFF5CBACFBEDFF11FD18.taxon	diagnosis	Diagnosis: — Lasianthus hoabinhensis is closely related to L. attenuatus Jack (2012: 13) in having densely tomentose or setose on branches and axillary inflorescences, but it can be distinguished from latter by its leaf blades 15 – 25 × 5 – 8 cm (vs. 5 – 12 × 2.5 – 5 cm), secondary veins 9 – 11 pairs (vs. 6 – 8 pairs), calyx tube 3 – 4 mm long (vs. ca. 1 mm long) and lobes 7 (vs. 5), corolla lobes 6 or 7 (vs. 5), 3 – 4 mm long (vs. 4 – 5 mm long), and pyrenes 6 or 7 (vs. 5). Shrubs up to 3 m tall; branches ca. 5 mm in diam., densely tomentose or sometimes setose, blackish when dry; internodes 5 – 10 cm. Leaves opposite; blades oblong, oblong-ovate or elliptic-lanceolate, 15 – 25 × 5 – 8 cm, coriaceous, adaxially glabrous, abaxially tomentose, apex acute to cuspidate-acuminate, 10 – 15 mm long, base more or less oblique, slightly cordate, margin entire, midrib flat adaxially, prominent abaxially, secondary veins 9 – 11 pairs, ascending at the angle of 45 – 60 ° from midrib, curved to the margin, flat adaxially, prominent abaxially, tertiary veins subparallel, prominent abaxially; petioles 1 – 2 mm long, tomentose. Stipules narrowly triangular, 2 – 3 mm long, densely tomentose on both surfaces. Inflorescences axillary, cymose, up to 4 - flowered, covered by persistent bracts. Bracts numerous, filiform, 8 – 12 mm long, tomentose, forming a dense head. Flowers sessile, 16 – 20 mm long. Calyx obconical to campanulate, 4 – 6 mm long, hirsute, tube 3 – 4 mm long, pale-purple in vivo, lobes 7, linear, 2 mm long, hirsute on both surfaces. Corolla tube cylindrical, 12 – 14 mm long, tube 9 – 10 mm long, white, sparsely hirsute outside, lobes 6 or 7, ovate-triangular, 3 – 4 mm long, sparsely hirsute outside, villous inside. Stamens 6 or 7, inserted at corolla tube, filaments short, anthers oblong, 1.5 – 2 mm long. Ovary with 6 or 7 locules, style 15 – 17 mm long, glabrous, stigma 6 - or 7 - lobed, 0.5 – 0.8 mm long. Drupes subglobose to ovoid, 8 – 12 mm long, ca. 7 mm in diam., minutely hirsute, blue when ripe; pyrenes 6 or 7. Seeds ovoid, 2 – 3.5 mm long, smooth on the abaxial face, brown when dry.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFDFFF5CBACFBEDFF11FD18.taxon	distribution	Distribution, habitat and phenology: — The new species is only known from Phu Canh Nature Reserve, Da Bac District, Hoa Binh Province, Northern Vietnam. This species grows under the shade of the evergreen broadleaf forests, at an elevation of 1000 – 1200 m. Flowering and fruiting specimens were collected in October.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFDFFF5CBACFBEDFF11FD18.taxon	etymology	Etymology: — The new species is named after its type locality, Hoa Binh Province. Vernacular name: — Xú hƯƠng hòa bình (Vietnamese). Preliminary conservation assessment: — Lasianthus hoabinhensis is known only from a single population with about 100 individuals in Phu Canh Nature Reserve of Hoa Binh Province. A comprehensive survey of remaining forest near the type locality and neighboring provinces is needed to accurately investigate the distribution range and number of populations of the species. Due to lack of current data and according to IUCN criteria (IUCN 2024), the species is assessed as “ Data Deficient ” (DD).	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFDFFF5CBACFBEDFF11FD18.taxon	description	Notes: — The new species resembles L. attenuatus Jack (2012: 13) which is widespread in tropical and subtropical regions in Asia, but differs from that species in the several characters. Lasianthus hoabinhensis is also similar to L. pilosus Wight (2012: 75), which is distributed in Malaysia and Thailand, but distinguished by its shorter petioles (1 – 2 mm long vs. 3 – 5 mm long), larger bracts (8 – 12 mm long vs. 4 – 5 mm long), smaller calyx (tube 3 – 4 mm long, lobes ca. 2 mm long vs. tube ca. 8 mm long, lobes ca. 5 mm long), and smaller corolla tube (9 – 10 mm long vs. ca. 15 mm long), and reddish-orange fruits (vs. blue). The comparison among L. hoabinhensis, L. attenuatus and L. pilosus is shown in Table 2.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFEFFF5CBACFAA3FE5CF85B.taxon	materials_examined	TYPE: — LAOS. Attapeu Province: Sanamxai District, roadside, at the edge of evergreen forests, 14 ° 47 ′ 18.18 ″ N, 106 ° 25 ′ 24.90 ″ E, 183 m elevation, 6 July 2019, P. Souladeth, S. Tagane, N. Tanaka, K. Souttakone, Y. Suyama, K. Phengmala, N. Ishii L 3024 (holotype FOF!, isotypes KAG [KAG 129297], TNS!).	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFEFFF5CBACFAA3FE5CF85B.taxon	distribution	Distribution, habitat and phenology: — Laos (Attapeu and Champasak Provinces) and Vietnam (Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province). It grows in lowland evergreen forests, 20 – 190 m elev. Flowering and fruiting specimens were collected in July to August. Vernacular name: — Xú hƯƠng lào (Vietnamese). Notes: — Lasianthus laoticus was described from Laos by Tagane et al. (2023) based on two collections, Souladeth et al. L 3024 and L 2222. This species is easily recognizable in the field in having brownish hairy branches, cordate leaf base, secondary veins 8 – 11 pairs, long peduncles 1.5 – 3 cm long, flowers white with a faint tinge of yellow, and fruits subglobose or ovoid, black when ripe.	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
03DB87E7FFFEFFF5CBACFAA3FE5CF85B.taxon	description	Specimen examined: — VIETNAM. Ba Ria-Vung Tau Province: Binh Chau-Phuoc Buu Nature Reserve, in evergreen forests, 10 ° 35 ′ 12.04 ″ N, 107 ° 33 ′ 25.00 ″ E, 28 m elev., 16 August 2022, V. - S. Dang & L. V. Son Dang- 664 (VNM [VNM 00070336]).	en	Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro, Naiki, Akiyo (2025): Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam. Phytotaxa 694 (1): 57-67, DOI: 10.11646/phytotaxa.694.1.4, URL: https://doi.org/10.11646/phytotaxa.694.1.4
