Camchaya bolavenensis Noyori, Komada, Soulad. & Tagane, 2022

Noyori, Wataru, Komada, Natsuki, Souladeth, Phetlasy & Tagane, Shuichiro, 2022, Camchaya bolavenensis (Asteraceae: Vernonieae), a new species from Bolaven Plateau, southern Laos, Phytotaxa 536 (1), pp. 1-6 : 2-6

Camchaya bolavenensis Noyori, Komada, Soulad. & Tagane , sp. nov. Figs 1–3.

Diagnosis: — Camchaya bolavenensis is morphologically similar to C. thailandica Bunwong et al. (2012: 53) of Thailand and C. gracilis of Thailand and Laos in the point that all of them have terminal and axillary capitulescences and phyllaries without marginal spines. However, C. bolavenensis is distinguished from these two by its basally decumbent stem (vs. entirely erect), margin of lamina with distinct (1–)2–3 teeth which is 2–4 mm long (vs. entire or serrate with 5–10 teeth less than 1 mm long), invisible secondary veins (vs. prominent and clearly visible abaxially), and 10–30 florets per capitulescence (vs. 50–70 florets).

Type:— LAOS. Champasak Province, Paksong District, near Nong Luang Village, Dong Hua Sao National Protected Area (Bolaven Plateau), 15°03′43.35″N, 106°12′37.47″E, 1252 m elev., 17 Dec. 2019, Souladeth P., Tagane S., Kongxaysavath D., Rueangruea S., Suddee S., Suyama Y., Suzuki E. L3349 (holotype FOF [ FOF0005197 !] , isotypes BKF, KAG [ KAG155714 !]) .

Herbs, probably perennial, up to 50 cm tall. Stem decumbent at lower part, erect in middle and upper part, terete, inconspicuously ribbed, sparsely covered with short filiform hairs and glands, 1–2 mm in diam. Leaves alternate, sessile; blades narrowly obovate to linear, 3.5–6.2 × 0.4–1 cm, apex acuminate, base cuneate to attenuate, margin serrate with (1–)2–3 teeth, 2–4 mm long on each side, chartaceous, gray-green adaxially, pale greenish gray abaxially, glabrous on both surfaces except a few filiform hairs on margin near lamina base, very sparsely covered with capitate glands on both surfaces, midrib slightly prominent abaxially, secondary and tertiary veins invisible. Capitulescences terminal and axillary, solitary or corymbose. Capitula pedunculate, 1.3–1.5 cm long in anthesis, involucres campanulate, 3–5 mm in diam. Receptacle convex, ca. 4 mm in diam, glabrous, with sessile glands. Phyllaries 3–4 seriate, imbricate, dull gray-green with reddish purple apices, glabrous adaxially, very sparsely hairy, glandular abaxially, margins entire, sparsely ciliolate, apex acuminate, the outer phyllaries ovate-lanceolate, 6 × 2.2 mm, the middle ones ovate-elliptic, 7.5–7.8 × 3–3.2 mm, the inner ones lanceolate, 8–9 × 1.5–2 mm long. Florets 10–30; corollas infundibular, purple, sparsely hairy, tubes 4–6 mm long, whitish, lobes 5, 3– 4 mm long, apex obtuse to slightly capitate with dense glands. Stamens 5, ca. 6 mm long, anthers linear, 1.7–2 mm long, apex acute, base sagittate, apical appendage ovate, ca. 0.4 mm long, filaments ca. 4.6 mm long, glabrous, connate to corolla near the corolla mouth, free part 1–1.1 mm long. Styles linear, 8–9 mm long, purple, pubescent, stigmas 2-branched, branches 2–2.5 mm long, ovary elliptic, 1.1–1.2 × 0.3–0.4 mm, without carpopodium. Achenes obovate-turbinate, ca. 2.2 mm long, 10-ribbed. Pappus absent. Pollen echinolophate, 6-porate, without micropuncta.

Etymology: —The specific epithet bolavenensis refers to the type locality, Bolaven Plateau.

Distribution: — Laos (Champassak Province, Bolaven Plateau).

Additional specimens examined: — LAOS. Champasak Province, Paksong District, near Nong Luang Village, Dong Hua Sao National Protected Area (Bolaven Plateau), 15°04′19.26″N, 106°12′38.67″E, 1248 m elev., 10 Dec. 2018, Tagane S., Nagahama A., Souladeth P., Pisuttimarn P. L2011 ( FOF, KAG [ KAG128113 ], KYO); ibid., 15°04′14.58″N, 106°12′33.72″E, 1246 m elev., 17 Dec. 2019, Souladeth P., Tagane S., Kongxaysavath D., Rueangruea S., Suddee S., Suyama Y., Suzuki E. L3321 ( BKF, FOF, KAG [ KAG155686 ]) .

Habitat and ecology: — Camchaya bolavenensis grows on wet thin soil over large and exposed sandstone boulders, where it grows with sphagnum moss (Sphagnum sp.), Canscora andrographioides Griff. ex Clarke (1875: 431) , Eriocaulon cormosum Souladeth et al. (2020: 2) , Eriocaulon sp. and some species of Poaceae . Flowering specimens were collected in December.

Vernacular name: —Mouk Nong Luang (ມ̥ƊmŊƱǥmOວǥ), suggested here.

Preliminary conservation status: —Critically Endangered (CR). Camchaya bolavenensis is known only from the two populations on the plateau of Bolaven, which located within the protected area of the Dong Hua Sao National Protected Area. We observed each population less than 100 flowering stalks and they are possibly consisted of a few genets. The extent of occurrence (EOO) regarded as open rocky grassland on the plateau is less than 500 km ² and the area of occupancy (AOO) for this species is 4 km ² (using 2 km cell width). Considering these information as well as the area is popular with tourists, which might increase disturbance in the area and which could affect the survival of this species, and the vicinities are heavily affected by habitat loss due to land conversion to agriculture, mining and dams ( Delang et al. 2013), a preliminary conservation status can be assessed as Critically Endangered according to the IUCN criteria 2ab(iii) ( IUCN Standards and Petitions Committee 2019).

Notes: —In addition to Camchaya gracilis , C. bolavenensis is different from C. loloana , another species of the genus distributed in Laos, in having basally decumbent stem (vs. erect in C. loloana ), glabrous leaves (vs. covered with whip-shaped hairs), and entire phyllaries (vs. with spines).