Zingiber cardiocheilum Škorničk. & Q.B.Nguy

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 : 206-208

Zingiber cardiocheilum Škorničk. & Q.B.Nguy ễn, sp. nov. (sect. Dymczewiczia)

Similar to Zingiber rufopilosum in its fusiform downward-facing inflorescence, but differs in the glabrous leaf sheaths, ligules and margins of the laminae, narrower inflorescence 4–11 × 1.5–1.8 cm, entire labellum and glabrous ostiole (vs. leaf sheaths and ligules densely pilose, margins of laminae pilose, inflorescence c. 6 × 3 cm and distinctly bifid labellum with incision about 1/3 of its length and ciliate ostiole).

Type: — VIETNAM. Vĩnh Phúc Province, Tam Đảo N. P, 583 m, 21°26’51.3”N, 105°37’27.9”E, 19 September 2011, Nguyễn Quốc Bình, Jana Leong-Škorničková, Tr ần H ữu Đăng, VNMN-B 1446 (holotype SING (inclusive spirit), isotypes E, P, PR, VNMN (incl. spirit). Fig. 3 .

Clump forming rhizomatous herbs. Rhizome to 1 cm in diam., branched, 3–5 cm between leafy shoots, externally dirty white to cream coloured, internally ochraceous, weakly aromatic, scales broadly triangular, up to 1.5 cm long, rusty brown, striate, glabrous. Leafy shoot to 1.2 m tall, with 20–25 leaves, base swollen c. 17 mm in diam., dark red, basal part of pseudostem leafless for 1/4–1/3; bladeless sheaths green with faint dark red tinge towards base; leaf sheaths dark green, glabrous; ligule 3–5 mm long, shallowly bilobed, light green, glabrous; petiole absent; lamina narrowly ovate, up to 30 × 2.5(–3.0) cm, gradually tapering to narrowly acute apex, base rounded, above dark glossy green, smooth (no prominent plication), lighter green beneath, fairly leathery texture, glabrous both sides. Inflorescence terminal, hanging down; spike 4–11 cm long, 1.5–1.8 cm broad, spindle shaped, consisting of 20–45 bracts; bracts green, glossy, obovate, lowermost c. 5 bracts sterile, up to 2.3 × 2.3 cm (gradually smaller towards the apical part of inflorescence), apex broadly acute to obtuse; enclosing 2 flowers per bract (occasionally 3 flowers at the basal bracts, and only 1 in uppermost bracts). Bracteole obovate triangular, 4–10 × 2–4 mm, unequally folded with one keel, translucent white, glabrous externally and internally. Flower 3–4 cm long; calyx c. 12 mm long, translucent white, glabrous, with two inconspicuous teeth at apex (appears truncate), with unilateral incision 4–7 mm; floral tube 18–25 mm, externally and internally white, externally glabrous, internally sparsely puberulous; dorsal corolla lobe ovate-triangular, 10–14 × 6–8 mm, semi-translucent light yellow, sometimes with faint pinkish tinge, darker towards apex, externally and internally glabrous, apex acute, mucronate, mucro c. 1 mm; lateral corolla lobes ovate triangular, 10–12 × 5–6 mm, semi-translucent light yellow, sometimes with faint pinkish tinge, darker towards apex, externally and internally glabrous, apex acute; labellum c. 11 mm long, c. 9 mm broad, broadly ovate, dark red to deep maroon violet, sometimes with yellow blotches, velvety in appearance, margins of the labellum reflexing at apical half (resulting in heart shape of the labellum); lateral staminodes 1.5–3.0 × 1.5 mm, ovate to broadly triangular, connate to the labellum by basal 1/2, yellow or with red patch. Stamen 12 mm long; filament 2–3 mm long, 3–4 mm broad at base, 2.5–3.0 mm broad at apex, light yellow, glabrous; anther 9–11 × 3–4 mm, connective tissue light yellow, glabrous, anther crest 1.5–2.0 mm, wrapped around stigma, dark yellow, sometimes with red tinge, glabrous; anther thecae 7–9 mm long, dehiscing along entire length. Epigynous glands two, c. 6 mm long, c. 0.5 mm in diam., ochraceous, sometimes with pink tinge, apex acute. Ovary nearly spherical, 2 × 2 mm, white, glabrous, trilocular with central placentation. Style white, glabrous, stigma c. 1.5 mm long, slightly thicker than style, white with a pink tinge at dorsal part, ostiole front-facing, glabrous. Fruit and seeds not seen.

Etymology:— Derived from Greek, the epithet denotes the heart-shaped appearance of the labellum.

Distribution & IUCN preliminary assessment:— So far known only from the type locality in Tam Đảo National Park. While this species is under protection of the National Park, we propose to treat this species for the time being as vulnerable (VU D1 and D2) as the AOO is less than 20 km 2 and only a few hundred individuals in a few subpopulations at one location were encountered during our fieldwork that covered various parts of Tam Đảo National Park.

Ecology and phenology:— Growing on slopes in evergreen broadleaved forest around 600 m. Flowering in late

August to early October. Bumble-bees were observed to effectively pollinate the flowers.

Figures

FIGURE 3. Zingiber cardiocheilum. A. Habit. B. Inflorescence (in natural hanging down position) with detail of flowers in side view. C. Rhizome (scale in cm). D. Flower (front view). E. Detail of ligules (scale bar in mm). F. Dissection (from left): floral tube with ovary, calyx and anther (front view; image rotated 180°), dorsal and lateral corolla lobes, labellum with lateral staminodes, (scale bar in mm). G. Detail of anther (front view), ovary and epigynous glands (scale bar in mm). Photo: Jana Leong-Škorničková.