Zingiber yersinii Škorničk., H.Đ.Tr, 2015

Leong-Škorničková, Jana, Bình, Nguy ễn Qu ốc, Đăng, Tr ần H ữu, Šída, Otakar, Rybková, Romana & Vương, Trương Bá, 2015, Nine new Zingiber species (Zingiberaceae) from Vietnam, Phytotaxa 219 (3), pp. 201-220 : 217-219

Zingiber yersinii Škorničk., H.Đ.Tr ần & Rybková, sp. nov. (sect. Zingiber )

Similar to Z. discolor in the size of the inflorescence and the coloration of the flowers, but differs by the thin slightly plicate leaf blades that are bright mid-green on both sides, pubescent pulvinus and reflexed spreading obovate lateral staminodes (vs. smooth coriaceous leaf blades adaxially dark green and abaxially prominently coloured with a glossy dark purple-violet, glabrous pulvinus and elliptic to narrowly obovate, lateral staminodes held upwards, not spreading).

Type: — VIETNAM. Khánh Hòa Province, Hòn Bà Nature Reserve, 1518 m, 12°7’09.4”N, 108°56’49.8”E, 3 July 2010, Jana Leong-Škorničková, Romana Rybková, Jan Ponert, Tr ần H ữu Đăng, Trịnh T ấn Thành, TrƯƠng Quang Tâm, TrƯƠng Bá VƯƠng HB-77 (holotype SING (inclusive spirit), isotype E, PR, VNM, Hòn Bà Nature Reserve). Fig. 9 .

Clump-forming rhizomatous herbs. Leafy shoots to 0.8 m long, arching with c. 15 leaves, basal 1/4–1/3 of pseudostem leafless, sheathed by 3–5 leafless sheaths; bladeless sheaths 3–5, brown-maroon, puberulous; leaf sheaths dark green with brown-maroon tinge at base, plain green towards the apex of pseudostem), puberulous; ligule up to 1 cm long, bilobed, lobes green thin, slightly puberulous to almost glabrous; petiole inconspicuous, consisting of light green, pubescent pulvinus; lamina narrowly elliptic, up to 22.0 × 6.5 cm (measured from dry material), weakly plicate, bright mid green adaxially, slightly lighter abaxially, glabrous both sides, margin entire, base obtuse, apex attenuate. Inflorescence radical, erect; peduncle up to 10 cm long, with 4–8 sheathing bracts; spike up to 9.0 × 3.5 cm, ovoid to ellipsoid, composed of 10–30 bracts; bracts broadly ovate to broadly elliptic, 3.0–3.5 × 1.8–2.0 cm (smaller towards apex), light green at base, with rich red-brown tinge at apical half, margin translucent, c. 1 mm broad, glabrous on both sides, enclosing a single flower; bracteole c. 2.6 cm long, semi-translucent cream at base, light green towards the apex, glabrous externally and internally. Flower c. 5 cm long; calyx c. 16 mm long, semi-translucent, greenish-white, glabrous, apex with 3 inconspicuous teeth, unilateral incision c. 9 mm; floral tube c. 26 mm long, cream white to pale yellow, externally glabrous, internally sparsely puberulent in apical part; dorsal corolla lobe elliptic, c. 27 × 10 mm, cream white to pale yellow with translucent veins, glabrous externally and internally, apex acute; lateral corolla lobes narrowly triangular-ovate, up to 23 × 4 mm, cream white to pale yellow with translucent veins, glabrous externally and internally, apex acute; labellum 22–24 × 14–16 mm (c. 22 mm inclusive the staminodes), irregularly ovate, with irregularly obtuse to rounded apex; pale yellow at base and basal half of central median, the rest purple with small yellow blotches; lateral staminodes 14–15 × 6–7 mm, obovate, connate to labellum fully or by basal 4/5, cream white to pale yellow, reflexed (spreading). Stamen c. 18 mm long (measured unmanipulated); filament reduced; anther c. 18 mm long (crest not straightened) connective tissue cream to pale yellow, anther crest c. 13 mm long (straightened), dull yellow, wrapped around stigma, apex acute; anther thecae c. 10 mm long, dehiscing along the whole length. Epigynous glands two, 5 mm long, c. 0.5 mm in diam. at base, dull yellow. Ovary almost globose, c. 3.5 × 4.0 mm, pale yellow-green, glabrous. Style white, stigma ciliate, c. 0.5 mm long, slightly thicker than style, ostiole front-facing, ciliate. Mature fruits not seen.

Etymology:— The specific epithet honours Alexandre Emile Jean Yersin, a well-known physician and bacteriologist, who spent a considerable part of his life in Nha Trang, southern Vietnam, and had a house on the top of Hòn Bà mountain where this species occurs.

Distribution & IUCN preliminary assessment:— Currently known only from the type locality at the top of Hòn Bà mountain, but this species is expected to be found in adjacent areas (particularly from Bidoup Núi Bà N.P.) as the exploration progresses.

Ecology and phenology:— This species appears to be fairly rare in broadleaved evergreen forest on Hòn Bà N.R. It has been seen only near the top at an elevation of c. 1500 m. Initiation of flowers at the type locality was observed in July and presumably continues through August, followed by fruiting, to be predicted to last at least until October.

Figures

FIGURE 9. Zingiber yersinii. A. Habit. B–C. Detail of ligule. D–E. Inflorescence. F. Flower (front view). G. Dissection (from left): dorsal corolla lobe, two lateral corolla lobes, labellum with lateral staminodes connate to it, Floral tube with ovary and stamen attached (calyx removed), bracteole, bract; scale bar in cm). H. Detail of ovary with epigynous glands and anther (side and front view). Photo: Jana Leong-Škorničková.