Biermannia longicheila Aver. & Nuraliev, 2018

Averyanov, Leonid V., Nuraliev, Maxim S., Kuznetsov, Andrey N. & Kuznetsova, Svetlana P., 2018, Biermannia longicheila (Orchidaceae, Aeridinae), a new species from southern Vietnam, Phytotaxa 343 (2), pp. 194-198 : 194-197

Biermannia longicheila Aver. & Nuraliev , sp. nov. ( Fig. 1 & 2 )

Type:— VIETNAM. Gia Lai Province: K’Bang District, K’rong Municipality, Kon Ka Kinh National Park, 25 km NW of K’Bang Town, forest, not far from river, 14°18’27’’N 108°26’52’’E, 620 m, 9 May 2017, Nuraliev, Kuznetsov, Kuznetsova 1726 (holotype LE: LE 01041427).

Digital epitype:—Plate d-EXSICCATES OF VIETNAMESE FLORA 0302/Nuraliev 1726 ( MW: MW-DigiPic0000007) ( Fig. 1 ).

Image of epitype at MW as well as the drawing available at https://depo.msu.ru/open/public/item/MW-DigiPic0000007 and https://depo. msu.ru/open/public/item/MW-DigiPic0000008

The new species may be close to the Himalayan B. bimaculata ( King & Pantling 1895: 340) King & Pantling (1898b: 200) , but differs from the latter by its twice larger, widely opening flowers about 20 mm across (vs. hardly opening flowers, 8–10 mm in diameter), long narrow sepals, 12–13 mm (vs. narrowly ovate sepals, 7–8 mm), long narrowly conoidal, acute lip 11–12 mm long (vs. shortly conoidal 5–6 mm long), concave disc with broad half-ovoid callus bearing small central cavity (leading to the spur) at the base (vs. disc with two elongate basal calli without cavities and spur), and by the large, prominent subglobular callus at the front of column foot apex (vs. no swellings on column foot).

Monopodial, epiphytic herbs, generally glabrous. Stem (0.6)1.0–2.5(3.0) cm long, densely covered by distichous leaf sheaths, slightly flattened, with many pale green wiry roots clustered near stem base. Leaves (4)5–7(8), sessile, jointed, narrowly elliptic, sometimes slightly falcate, (4.5)5.0–8.0(8.5) × (1.4)1.6–2.2(2.4) cm, apex with two acute oblique unequal lobes. Inflorescence rather fleshy, glabrous; peduncle terete, (4)5–8(10) mm long, with 1–3(4) distant sterile triangular acute bracts, bracts (1.0)1.2–1.5(2.0) mm long and wide; rachis flattened (rectangular in cross section) with (4)6–8(10) distichous triangular floral bracts; floral bracts separated by (2.5)3.0–4.0(4.5) mm, triangular, acute, (2.0)2.2–2.4(2.8) mm long and wide; 1–3 flowers blooming simultaneously; inflorescence developing for a long time and thus flowers occupy its apical half. Flowers widely opening, fugacious, resupinate or not. Pedicel and ovary light green, hairy with short, scurfy, scattered brownish hairs, terete, triangular, 6-grooved, (3.8)4.0–4.4(4.8) mm long, 0.8–1.0 mm in diameter. Sepals subequal, broadly lanceolate to narrowly ovate, apiculate, straight, later recurved, (10.0)10.5–12.5(13.0) × (3.0)3.2–3.4(3.6) mm, pure white or with light yellowish-green tint near base; lateral sepals attached to column foot. Petals triangular, broadly lanceolate, acute, straight, as broad as sepals but slightly shorter, pure white. Lip at base with hemispheric, spur-like protrusion 0.8–1.0 mm in diameter, trilobed, firmly adnate at right angle to column foot, lying almost parallel to column, (8.0)8.5–9.0(10.0) × (3.2)3.5–4.0(4.2) mm, white, with four pale brown blotches near base; lateral lobes narrowly triangular, slightly falcate, erect, forward directed, acute, 1.0– 1.2 mm long; median lobe narrowly conoidal, (5.6)5.8–6.2(6.5) mm long, 2.0– 2.2 mm in diameter. Disc concave, at base with broad half-ovoid callus bearing small central cavity (leading to the spur) and with 2 pillow-like flattened, forwardly directed cushions at base of midlobe. Column white 2.2–2.4 × 1.8–2.0 mm; stigma almost circular, concave; column foot as long as column, at apex with white or pale purple prominent subglobular callus, 1.0– 1.2 mm in diameter, slightly bifid at apex. Operculum hemispheric, 1.2–1.4 mm in diameter, with an insignificant beak. Pollinia 2, globular, 0.35–0.40 mm in diameter, with a hardly visible cavity; stipe broadly ovate, concave, 0.5–0.6 × 0.4–0.5 mm wide, attenuate at base, viscidium half this size, ovate. Fruit and seeds unknown.

Etymology:— The specific epithet refers to the long narrow lip of this species.

Habitat, phenology and conservation status:— Monopodial canopy epiphyte. Primary evergreen broad-leaved lowland forest along river valleys, 620 m. Flowering April–May. Known only from a single plant. Estimated IUCN Red List status—DD.

Distribution:— Endemic to the type locality thus far.

Notes: —The two species of the genus previously recorded in Vietnam, i.e. common B. calcarata Averyanov (1988: 429) and insufficiently known B. sigaldii Seidenfaden (1992: 433; Seidenfaden 1992, Averyanov 1994, Pham Hoang Ho 2000, Averyanov & Averyanova 2003, Nguyen Tien Ban et al. 2005) have no morphological similarity to B. longicheila . Records of B. bimaculata for Vietnam (Xu et al. 2010, Zhou et al. 2016) remain highly doubtful because they are not supported by any cited specimens.

Figures

FIGURE 1. Biermannia longicheila Aver. et Nuraliev. Digital epitype, Averyanov & Nuraliev 0302 made from the type, Nuraliev et al. 1726. Photos by M. Nuraliev, correction and design by L. Averyanov.

FIGURE 2. Biermannia longicheila. A.Flowering plant.B. Inflorescence. C. Rachis.D. Intact flowers, frontal and side views.E. Flattened flower, lip and pedicelate ovary. F. Intact lip, view from above. G. Intact lip, side view and sagittal section. H. Intact column and column foot, frontal view. I. Intact column and column foot, side view. J. Operculum, frontal view, side view and view from below. K. Pollinarium, frontal view and view from behind. All drawn from the type (Nuraliev et al. 1726) by L. Averyanov.