taxonID	type	description	language	source
731884124926FF98FF1D9812FB8FFEAD.taxon	materials_examined	TYPE: — LAOS. Champasak Province, Dong Hua Sao National Park [Bolaven Plateau], Paksong District, near Nong Luang Village, in lower montane forest, near a stream, 15 ° 04 ′ 31.58 ″ N, 106 ° 12 ′ 30.72 ″ E, 1226 m elev., P. Souladeth, S. Tagane, D. Kongxaysavath, S. Rueangruea, S. Suddee, Y. Suyama, E. Suzuki L 3337 [fl. & fr.] (holotype FOF!, isotype KAG 155702!, TNS). Lasianthus bolavenensis is characterized by glabrous twigs, glabrous leaves except with sparse hairs on midrib and secondary veins abaxially when young, 4 or 5 pairs of secondary veins, and semi-orbicular bracts, by which combination it can be distinguished from the other species of Lasianthus in Laos and its surrounding countries. In Indochina, it is similar to L. bidoupensis Dang & Naiki in Dang et al. (2019: 191), an endemic species to southern Vietnam, in having almost glabrous twigs and leaves, elliptic-oblong lamina, 5 - merous flowers, pinkish-white calyx, and bluish fruits, but different in having smaller leaf size (4 – 11.3 × 1.6 – 3.8 cm in L. bolavenensis vs. 16 – 24 × 6 – 8.5 cm in L. bidoupensis), fewer secondary veins (4 or 5 vs. 6 or 7), larger anthers (2.8 mm long vs. 1 – 1.2 mm long), and glabrous style (vs. pubescent) (Table 1).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124926FF98FF1D9812FB8FFEAD.taxon	description	Description: — Shrub, 1.5 m tall. Twigs glabrous, blackish when dry, terete; internode 1.7 – 4 (– 7.5) cm. Leaves opposite, petiolate; petiole 0.8 – 1.3 cm long, glabrous; blade ovate-elliptic, elliptic-oblong, elliptic, (4 –) 5.5 – 11.3 × (1.6 –) 2.1 – 3.8 cm, coriaceous, glabrous except on midrib and secondary veins abaxially which is sparsely hairy, adaxially dark grayish brown, abaxially dark brownish yellow to gray-green, apex acuminate to aristate, tip pointed ca. 1.2 mm long, base cuneate, sometimes oblique, margin entire, midrib slightly concave adaxially, prominent abaxially, secondary veins 4 or 5 pairs, prominent abaxially, tertiary veins parallel. Stipule triangular, 2 – 2.5 mm long, apex acute, densely pubescent near margin. Inflorescence axillary, cymose, 1 – 4 flowered, sessile; bract semi-orbicular, 1 – 1.2 mm long, apex truncate, margin densely pubescent. Flowers subsessile; calyx pinkish white, ca. 6 mm long, tube ca. 4 mm long, glabrous, lobes triangular, ca. 2 mm long, apex acute, pubescent near apex; corolla pinkish white to white, cylindrical-campanulate, ca. 1 cm long, tube ca. 8.5 mm long, outside villous in upper 3 / 4, inside villous in upper 1 / 2, lobes 5, triangular, ca. 1.5 mm long, apex acute, villous. Stamens 5, inserted in corolla tube, anthers ca. 2.8 mm long, filament basally connate to corolla, free part ca. 0.2 mm long; ovary 5 - locular, style 4 mm long, glabrous, stigma 4 - lobed, ca. 2 mm long. Fruits subglobose or oblong, 1.1 – 1.2 cm long, ca. 5 mm in diam., glabrous, blue when ripe; pyrenes 5. Seeds 5, ca. 6 mm long, blackish brown when dry. Additional specimen examined: — LAOS. Champasak Province, Dong Hua Sao National Protected Area, Seua Waterfall near Ban Nong Luang, 15 ° 04 ′ 02.6 ″ N, 106 ° 12 ′ 29.9 ″ E, 1147 m elev., 19 February 2019, P. Souladeth et al. L 2501 [fl.] (BKF, FOF!, KAG 128750!).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124926FF98FF1D9812FB8FFEAD.taxon	distribution	Distribution: — LAOS (so far known only from the Bolaven Plateau, Champasak Province). Habitat and Ecology: — The species was found in wet evergreen forest at elev. 1140 – 1280 m. Flowering specimens were collected in December and February, and fruiting in December.	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124926FF98FF1D9812FB8FFEAD.taxon	etymology	Etymology: — This specific epithet bolavenensis refers to the type locality, Bolaven Plateau. Vernacular name: — [(Xangsan Bolaven, “ Xangsan ” means Lasianthus in general in Lao and “ Bolaven ” refers to the Bolaven Plateau where the species occurs), proposed here]. Preliminary conservation assessment: — Critically Endangered (CR). From our observations by five field surveys in 2018 – 2020 (Souladeth et al. 2020, Tagane et al. 2020), Lasianthus bolavenensis is locally common but narrowly restricted in a small area on Bolaven Plateau: in wet evergreen forest at elevation between 1140 – 1230 m, and we estimate the area of occupancy is less than 10 km 2 and mature individuals less than 1000. The most area of its habitat is located within the protected area of Dong Hua Sao National Park (formerly Dong Hua Sao National Protected Area), but some of the vicinities are being converted to coffee plantations, which might bring negative impact for the survival of this species. Given this situation, we propose Critically Endangered (CR) according to B 2 b (ii, iii) (IUCN 2012) for the first conservation assessment for this species. Note: — Lasianthus bolavenensis is also similar to Lasianthus inodorus Blume (1826 – 1827: 998) subsp. inodorus, widely distributed in Bangladesh, Cambodia, China, India, Indonesia (Sumatra, Java), Thailand, and Vietnam, in glabrous twigs and leaves (or sparsely puberulous on lower leaf surface) and sessile inflorescence, but different in having 4 or 5 pairs of secondary veins (vs. 6 or 7 pairs), smaller bracts 1 – 1.2 mm long (vs. 3 – 6 mm long), and blueish oblong fruits (vs. dark orange-red turning black when mature and ovoid) (Table 1).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124924FF9DFF1D9F41FC3AF9D4.taxon	materials_examined	TYPE: — LAOS. Attapeu Province: Sanamxai District, roadside, at edge of evergreen forest, 14 ° 47 ′ 18.18 ″ N, 106 ° 25 ′ 24.90 ″ E, 183 m elev., 6 July 2019, P. Souladeth, S. Tagane, N. Tanaka, K. Souttakone, Y. Suyama, K. Phengmala, N. Ishii L 3024 (holotype FOF!, isotypes KAG 129297!, TNS!). Lasianthus laoticus is similar to L. kailarsenii Poopath, Vajrodaya & Napiroon in Napiroon et al. (2018: 208) of Thailand and L. longipedunculatus Parker (1925: 430) of Myanmar and Thailand in having conspicuous pedunculate cymes, but distinguished by appressed hairy twigs and petiole (vs. glabrous), reticulate tertiary veins (vs. parallel), and smaller triangle stipule ca. 1.8 mm long (vs. lanceolate, 3 – 4 mm long in L. kailarsenii and triangular, 2 – 5 mm long in L. longipedunculatus). In addition to these vegetative traits, L. laoticus differs from L. kailarsenii in having cylindrical-campanulate corolla with triangular lobes 3 mm long (vs. tuber, lobes oblong-lanceolate 1.5 – 2 mm long), longer style 4 mm long (vs. 1.5 – 2 mm), and from L. longipedunculatus in having shorter peduncles 1 – 3 cm long (vs. 4 – 10 cm long), smaller linear bracts ca. 2.2 mm long (vs. leaf-like, linear-lanceolate, 8 – 12 mm long), and triangular calyx lobes ca. 1 mm long (vs. oblong-lanceolate, 4 – 4.5 mm long) (Table 2).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124924FF9DFF1D9F41FC3AF9D4.taxon	description	Description: — Shrub, to 1 m high. Current year twig 2 – 3 mm in diam., flattened, appressed brownish hairy, glabrescent; internode 1.3 – 4.2 cm. Leaves opposite, petiolate; petiole 1 – 3 mm long, densely appressed hairy; blade ovate-oblong, 3.5 – 13 × 1.4 – 4.1 cm, subcoriaceous, adaxially dark yellow green, glossy, glabrous, abaxially gray green, densely hairy on midrib to tertiary veins, apex acuminate to aristate, tip pointed, 0.8 – 1.4 mm long, base cordate, margin finely undulate, midrib sunken adaxially, prominent abaxially, secondary veins 8 – 11 pairs, prominent abaxially, tertiary veins reticulate. Stipules triangular, ca. 1.8 mm long, brownish hairy outside, especially denser near margin and apex. Inflorescence axillary, cymose, solitary to 7 - flowered; peduncle 1.3 – 3 cm long, pubescent, glabrescent; bract linear, ca. 2.2 mm long, pubescent. Flowers subsessile to short-stalked; pedicels up to 2.2 mm long; calyx obconical, sparsely pubescent, tube ca. 2 mm long, lobes 4, triangular, ca. 1 mm long; corolla white with a faint tinge of yellow, cylindrical-campanulate, tube 6 – 9 mm long, outside glabrous, inside villous in upper 1 / 2, lobes triangular, ca. 3 mm long, apex apiculate, outside glabrous, inside villous, stamens 4, exerted from corolla, filaments basally connate to corolla, free part ca. 1.2 mm long, glabrous, anthers ca. 2.2 mm long, ciliolate; ovary 4 - locular, style ca. 4 mm long, glabrous, stigma 4 - lobed, ca. 0.9 mm long. Fruits drupaceous, subglobose or ovoid, 5 – 6 mm long, ca. 5 mm in diam., crowned by the persistent calyx, blackish brown when ripe, sparsely appressed hairy on the surface; the persistent calyx lobes 4, linear to linear-lanceolate, ca. 1 mm long, apex acute, hirsute; pyrenes 4, grooved on the dorsal curved face, obovoid, ca. 4 mm long, 2 mm wide. Additional specimen examined: — Champasak Province, Dong Hua Sao National Protected Area, 14 ° 53 ′ 44.73 ″ N, 106 ° 01 ′ 2.36 ″ E, 158 m elev., 13 December 2018, S. Tagane et al. L 2222 [young infl.] (FOF, KAG 128322).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124924FF9DFF1D9F41FC3AF9D4.taxon	distribution	Distribution: — Laos (so far known only from the two provinces, Attapeu and Champasak Provinces, located at the southern basin of Bolaven Plateau). Habitat and Ecology: — The species was found in lowland evergreen forest at 150 – 190 m elev. Flowering and fruiting specimens were collected in July.	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124924FF9DFF1D9F41FC3AF9D4.taxon	etymology	Etymology: — This specific epithet laoticus is derived from the country name where this species was discovered. Vernacular name: — [(Xangsan Lao, “ Xangsan ” means Lasianthus in general in Lao and “ Lao ” refers to the country where the species is discovered), proposed here]. Preliminary conservation assessment: — Endangered (EN). To date, Lasianthus laoticus is known only from two populations with each ca. 30 mature individuals in the lowland evergreen forest in lower elevations at the southern basin of Bolaven Plateau, at elevation of 158 and 183 m. Considering the distance between the two localities is ca. 18 km and same environment is found in the area, the estimated extent of occupancy for this species is 900 km 2. The localities we collected the above specimens are along a recently constructed logging road, and are being gradually deforested. Therefore, we suggest the category of this species as Endangered according to the IUCN criteria B 1 ab (i, ii, iii) (IUCN 2012). More accurate data on its population size and number of individuals is needed for developing a conservation plan. Notes: — Among the species of Lasianthus in Laos, L. laoticus is easily distinguished by its slender peduncles (vs. inflorescence sessile or subsessile in the other species). It is also similar to L. lancilobus of West Kalimantan in lamina size and slender peduncles but different from L. lancilobus in having shorter petiole 1 – 3 mm long (vs. 6 – 8 mm long in L. lancilobus), cordate leaf base (vs. acute to cuneate), 8 – 11 pairs of secondary veins (vs. 5 – 6 pairs), and small triangular calyx lobe 1 mm long (vs. lanceolate, 5 mm long) (Table 2).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124921FF9CFF1D9F88FC99FEE5.taxon	materials_examined	Type: — CAMBODIA. Montibus Knang Krepoeu, May 1870, L. Pierre 1257 (holotype A 00096531 image!, isotypes P 02285238, P 3981160, images!). Figure 5 Specimen examined: — LAOS. Attapeu Province, Sanamxai Diostrict, Bolaven Plateau, in lowland evergreen forest, 14 ° 48 ′ 19 ″ N, 106 ° 26 ′ 39 ″ E, 223 m elev., 6 July 2019, P. Souladeth et al. L 3067 (FOF, KAG, TNS).	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124921FF9CFF1D9F88FC99FEE5.taxon	distribution	Distribution: — Cambodia, Laos, Thailand, Vietnam.	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124921FF9CFF1D9F88FC99FEE5.taxon	vernacular_names	Vernacular name: — [(Xangsan Speu, “ Xangsan ” means Lasianthus in general in Lao and “ Speu ” refers to “ Knang Krepoeu ”, the type locality of this species, which is currently known as Kampong Speu Province), proposed here].	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
731884124921FF9CFF1D9F88FC99FEE5.taxon	discussion	Notes: — Lasianthus repoeuensis is distinguished from the other Lasianthus species in Laos by having lamina oblong-elliptic, elliptic-obovate, 9 – 17 × 2.8 – 4.3 cm, glabrous, adaxially blackish brown when dry, with 14 – 16 pairs of secondary veins, and stipule broadly triangular, 4 – 5 mm long.	en	Tagane, Shuichiro, Souladeth, Phetlasy, Tanaka, Nobuyuki, Phengmala, Kachonesak, Yahara, Tetsukazu (2023): Two new species and a new record of Lasianthus (Rubiaceae) in Laos. Phytotaxa 585 (2): 145-153, DOI: 10.11646/phytotaxa.585.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.585.2.5
