Goodyera umbonata Aver., V.C.Nguyen & Ormerod, 2023

Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Nguyen, Khang Sinh, Nuraliev, Maxim S., Nguyen, Cuong Huu, Ormerod, Paul A., Maisak, Tatiana V., Diep, Dinh Quang, Lyskov, Dmitry F. & Nong, Duy Van, 2023, New orchids in the flora of Vietnam VII (Orchidaceae: tribes Cypripedieae, Cranichideae, Orchideae, and Collabieae), Phytotaxa 619 (4), pp. 255-276 : 257-260

Goodyera umbonata Aver., V.C.Nguyen & Ormerod , sp. nov.

( Fig. 2 )

Diagnosis:—The new species differs from the morphologically closest Goodyera rhombodoides , G. thailandica and G. yamiana in smaller flowers, obliquely spatulate to narrowly obovate petals with truncate apices, cymbiform epichile with thin plicate margin, and prominent umbo at epichile center.

Type:— VIETNAM. Dak Lak Province: M’Drak District, Chu Mu Mountain , February 2022, Nguyen Van Canh AL 1545 (holotype LE01169141 https://en.herbariumle.ru/?t=occ&id=141019, drawing LE01124095 https:// en.herbariumle.ru/?t=occ&id=168135) .

Etymology:—The species name refers to the umbo-like callus on the lip epichile which distinguishes the new species from all its congeners.

Description:—Terrestrial herb with creeping rhizome and ascending leafy floriferous stem. Rhizome green, fleshy, (4)5–6(8) cm long, rooting at nodes. Floriferous stem (8)10–12(14) cm tall, glabrous, with (3)4–5(6) leaves distant in lower half. Leaves petiolate, glabrous; petiole and sheath (6)8–22(26) mm long, 1–2 mm wide; leaf blade uniformly grassy green adaxially, pale green abaxially, narrowly ovate, sometimes slightly oblique, gradually tapering to the apex, acute, (2.2)2.5–4.5(5) cm long, (1)1.2–1.5(1.7) cm wide. Peduncle erect, (6)7–8(9) cm long, finely papillose to shortly hairy, with 2–3 sterile bracts; bracts greenish, cuneate, acuminate, (5)6–15(16) mm long, 0.5–1.6 mm wide, shortly ciliate or fimbriate along margin, entirely glabrous; rachis finely hairy, usually with (10)12–16(18) laxly arranged flowers. Floral bracts light green, herbaceous, broadly ovate, concave, attenuate, finely serrulate or shortly fimbriate along margin, sparsely verruculose abaxially, (4)4.5–6(7) mm long, (0.8)1–1.5(1.6) mm wide, entirely glabrous. Pedicel and ovary grassy green, cylindrical, twisted, straight to strongly curved, (3.5)4–7.5(8) mm long, 0.8–1 mm in diameter, shortly sparsely papillulate to subglabrous. Flowers resupinate, hardly opening, (2.8)3–3.5(3.8) mm long. Sepals subequal, forward directed, narrowly ovate, cymbiform, slightly cucullate, obtuse, 1- nerved, (2.6)2.8–3(3.2) mm long, (1.4)1.6–1.8(2) mm wide, adaxially glabrous, abaxially sparsely papillulate to almost glabrous; lateral sepals slightly oblique. Petals obliquely spatulate to narrowly obovate, truncate to almost rounded at apex, 1-nerved, as long as sepals, 1.2–1.4 mm wide, glabrous, slightly eroded or almost entire at apex, tightly connivent in apical half with the median sepal forming together forward directed hood. Lip (3.2)3.4–3.8(4) mm long, 2–2.4 mm wide (being flattened), distinctly divided into hypochile and epichile; hypochile rather fleshy, concave, hemispheric, cup-like, 1.5–1.6 mm across, with numerous long thick multicellular hairs inside; epichile forward directed, broadly ovate, cymbiform, 1.5–1.7 mm long, 2.2–2.6 mm wide (being flattened), entire, with thin plicate margin, at base with 2 distinct papillulate callosities and in center with prominent umbo-like callus. Column (1.5)1.6–1.8(2) mm tall, with stout, shortly cylindrical base and 2 finger-like forward directed incurved rostellar arms 0.7–0.8 mm long, bearing anther distally and elliptic verruculose stigma proximally. Anther semi-globose, (1.2)1.4–1.6(1.7) mm long, with short triangular beak at front; pollinarium with very small, narrowly elliptic viscidium and numerous polyads arranged in two rows. Capsule suberect, fusiform, slightly attenuate at apex, 8–10 mm long, 2.5–3 mm in diameter, opening by 6 slits.

Ecology and phenology:—Evergreen broad-leaved submontane forests on granite. Flowers in February.

Distribution:—Endemic to Vietnam (Dak Lak Province: M’Drak District, Chu Mu Mountain).

Conservation status:—The species is known from a single location with several mature individuals observed. Pending comprehensive field studies in the area of its locus classicus, we estimate the conservation status of the species as Data Deficient (DD) according to the criteria proposed by the IUCN Standards and Petitions Committee (2023).

Notes:—In its habit and floral morphology, Goodyera umbonata is somewhat similar to its SE Asian congeners G. rhombodoides Averyanov (2007: 297) , G. thailandica Seidenfaden (1969: 109) and G. yamiana Fukuyama (1936: 18) . The new species differs from them in smaller flowers, obliquely spatulate to narrowly obovate petals truncate to almost rounded at apex, cymbiform epichile with thin plicate margin, and prominent umbo at epichile center. Goodyera umbonata represents an example of strict endemics of the mountainous area surrounding Langbian Plateau (a part of the so-called Central Highlands of Vietnam: Poyarkov et al. 2021), which is outlined in the biogeography of Eastern Indochina as the South Annamese Floristic Region ( Averyanov et al. 2003a,b).

Figures

FIGURE 2. Goodyera umbonata. A. Flowering plant. B. Portion of inflorescence. C. Floral bract, adaxial side. D. Flattened median sepal and petals, adaxial side. E. Median sepal, adaxial side. F. Lateral sepals, adaxial side. G. Petals, adaxial side. H. Lip, view from above and from below. I. Lip, side view and sagittal section. J. Artificially flattened lip, adaxial view. K. Intact column, and column with anther removed. L. Column with anther, view from above. M. Column with anther removed, view from above. N. Column and stigma, view from below. O. Anther, side view. P. Anther and pollinarium, view from below. Drawn from the type specimen (V.C.Nguyen AL 1545) by L.Averyanov and T.Maisak.