Schoenorchis tatonii Aver.

 Schoenorchis tatonii Aver., Taiwania 64(3): 295 (2019).

 Schoenorchis tatonii Aver., Photo by Leonid Averyanov

Family:

Orchidaceae.

Synonym:

Vietnamese name:

Trứng bướm

Distribution:

Vietnam

Description. 

Miniature monopodial branch and canopy epiphyte. Stem simple, erect or ascending, (1)1.5–3.5(4) cm long, leafy in apical two thirds, leafless in basal part, (2)2.5–3(3.5) mm in diameter, with many, straight to flexuose grey roots tufted at the base. Leaves grassy green, rugose, sessile, very fleshy, succulent, rigid, spreading at a wide angle to stem, straight, conduplicate to almost triangular in section or subterete (1.2)1.4–2.8(3) cm long, (1.8)2–2.8(3) mm wide, obtuse to acute at apex, slightly constricted in place of articulation with leaf sheath; leaf sheaths equitant, rigid, verruculose, completely covering the stem. Inflorescence lateral suberect at base, raceme or fewbranched panicle (1.2)1.5–3.8(4.2) cm long, scape and rachis light grassy green; scape (6)8–10(12) mm long, straight; rachis straight or arching, thin, slightly angled, (0.8)1–3.2(3.4) cm long, with many spirally arranged, lax flowers distant at (0.8)1–2.8(3) mm. Floral bracts minute, light green, triangular, acute, (0.3)0.4–0.5(0.6) mm long and wide. Pedicel and ovary light green, (0.7)0.8–0.9(1) mm long, about 0.3 mm in diameter, terete, glabrous. Flowers with unpleasant smell, not widely opening, (0.8)0.9–1(1.1) mm across, snow-white or with very light purple tint, glabrous; sepals and petals fleshy, forward directed and slightly recurved in apical half. Sepals ovate, very concave, blunt to obtuse at apex, (0.8)0.9–1.1(1.2) mm long, (0.55)0.6–0.7(0.75) mm wide; lateral sepals distinctly oblique. Petals oblong or narrowly ovate, rounded to blunt, as long as median sepal, (0.24)0.26–0.28(0.3) mm wide. Lip spurred, (1.3)1.4–1.6(1.7) mm long (from spur apex to the apex of median lobe), almost entire; median lobe very fleshy, oblong, (0.8)0.9–1(1.1) mm long, (045)0.5–0.6(0.65) mm wide, blunt to obtuse, straight, forward directed; at the base with massive fleshy transversal longitudinally furrowed callus almost completely closing entrance to the spur. Spur short, almost globular, parallel to column, (0.65)0.7–0.8(0.85) mm long and wide, with no prominent longitudinal septum or back-wall callus inside. Column light green, stout, very short, 0.2–0.3 mm tall and wide, with no wings; rostellum very small, broad, forward directed; stigma obscurely triangular to roundish. Anther cap brightly yellow, hemispherical, 0.2–0.3 mm in diameter, with very short, insignificant beak. Pollinarium 1, with 2 pollinia, flat ovate stipe (tegula) and flat oblong ovate viscidium. Pollinium ovoid or globular, hardly split into 2 unequal hemiovoid lobes. Fruit a narrowly obovoid to obovoid, light brown, longitudinally ridged capsule 2–3 mm long, 1.4–1.6 mm in diameter, with light grey capillitium fibres inside. All measurements were taken on fresh floral parts, which become much smaller after exsiccation in process ofherbarium specimen  preparation.

Type:

 – VIETNAM, herbarium specimen prepared on 2018 August 31, L. Averyanov, T. Maisak, AL 371 / 1 (holotype – LE01048676!), plant was collected in Kon Tum Province, Kon Plong District, Mang Den Town Area, Ngoc Linh Mountains, evergreen broad-leaved humid forest at elevation 1500–2000 m a.s.l., miniature branch epiphyte, not common, 21 October 2017, Nguyen Ta Ton, s.n.

Etymology:

The specific epithet honors orchid enthusiast Mr. Nguyen Ta Ton, the discoverer of the plant.

Habitat, phenology and conservation status.

Miniature branch epiphyte. Montane evergreen, broadleaved humid forests on granite at elevations of 1500–2000 m a.s.l. Not common. Flowers in August –September. Estimated IUCN Red List status – DD.

Distribution. 

Vietnam: Kon Tum Province (Kon Plong District, Ngoc Linh Mountains). Endemic.

Citation 

Averyanov, L.V. & Truong, Vuong & Nguyen Van, Canh & Nguyen, Khang & Maisak, T.. (2019). New Orchids (Orchidaceae) in the Flora of Vietnam II. Vandeae. Taiwania. 64. 285-298. 10.6165/tai.2019.64.285.