Zingiber bambusifolium (H.Lév. & Vaniot) L.Bai, Škorničk. & N.H.Xia

Zingiber bambusifolium (H.Lév. & Vaniot) L.Bai, Škorničk. & N.H.Xia in Taxon 73: 589. 2024.

Description. Perennial rhizomatous herb 0.6–1(–1.5) m tall. Rhizomes fleshy, tuberous. Vegetative rhizome units with or without a pseudo-neck, pseudo-neck 1–10 cm long, 5–6 mm in diam., with up to 8 internodes, internodes 0.5–1.8 cm long, externally cream when young but brown or reddish brown with age, internally pale yellow, or beige to peach coloured or dark purplish black, persistent scales brownish with densely glandular markings, smell a mixture of common ginger and mushroom, taste bitter; head broadly obconical, 1.5–2 cm long, 0.6–0.8 cm in diam. at base, 1–1.8 cm in diam. at apex, with 4–7 internodes, internodes 0.2–0.9 cm long; roots succulent, 5–7 mm in diam. Flowering rhizome units much smaller than vegetative rhizome units, cylindrical, 0.5–1.2 × 0.5–0.8 cm, with 2–3 internodes. Leafy shoots often arching, one per rhizome, occasionally up to 5 leafy shoots form a small clump, each shoot with (9–)12–22 well-developed leaves when flowering, basal ca. 1/5leafless; pseudostems to 1 cm in diam. at base, 0.4–0.6 cm in diam. in the middle; leaf sheath s open, green, sometimes lower ones purple tinged, glabrous or slightly pubescent; ligules bilobed, 1–6 mm long, membranous, semi-hyaline, glabrous, apices of the lobes obtuse to acute; petioles 1–5 mm long (slightly longer on the leaves in the middle of the shoot), consisting of pulvinus only, pale green, slightly pubescent; laminae herbaceous, narrowly elliptic, narrowly ovate to linear, 14–27 × 1.8–5 cm (length: width ratio 3.8–8.4), adaxially yellowish green to bluish green, smooth (not plicate) and glabrous, abaxially pale green or with burgundy tinges, glabrous or very sparsely pubescent along the midrib (hairs silvery, appressed), base obtuse on lower leaves, attenuate on upper leaves, apex acuminate, sometimes caudate on apical leaves. Inflorescences one to three per leafy shoot, radical; peduncles 1 to 27 cm long, 3.5–5 mm in diam., prostrate, buried under leaf litter; sheathing bracts narrowly ovate, 2.5–4 × 0.4–1.2 cm (when flattened), cream or green with pink, dark purple or red tinge (appear brownish red or red), pubescent externally; rachis densely pubescent; spikes narrowly ovoid when young, ovoid or obovoid when fruiting, 6–7 × 2–3 cm, with 7–19 bracts (1–2 basal bracts usually sterile, fertile one s each subtending a single flower); bracts linear, lanceolate, to narrowly ovate, laterally strongly recurved, almost appearing as a tube, 2.5– 4.5 × 0.6–1.4 cm (when flattened), green with pink, dark purple or red tinge (appearing brownish red or red), pubescent externally (hairs appressed), glabrous internally, apex acute to attenuate; bracteole lanceolate, involute laterally, 2.3–3 × 1–1.3 cm when flattened, pale greenish purple or red, pubescent externally (hairs appressed), glabrous internally, apex attenuate. Flowers 5–7.5 cm long, with floral tube slightly exserted beyond bracts, one to two flowers open at a time; calyx tubular to narrowly campanulate, with unilateral incision to about a third of its length, 11–18 mm long, 3–4.5 mm in diam., membranous, cream or cream with red tinge, apex three-teethed, sparsely pubescent; floral tube 3–4.5 cm long, shallowly curved, cylindrical at base (2.5–3 mm in diam.), narrowly funnel-shaped towards the apex (3.5–4.5 mm in diam.), cream, sparsely pubescent externally and near the throat internally; dorsal corolla lobe narrowly ovate, shallowly convex, 25–32 × 6–10 mm, cream to yellow with red tinge, sparsely pubescent externally, glabrous internally, apex mucronate; lateral corolla lobes narrowly ovate to narrowly triangular, usually deflexed, 24–32 × 4.5–7 mm, cream to yellow with red tinge, sparsely pubescent externally, glabrous internally, apex attenuate; labellum obovate to ovate, 23–30 × 12–14 mm, pure cream, or pale yellow with pale to dark purplish red tinge, glabrous on both sides, margin often crisped, apex rounded or slightly incised; lateral staminodes narrowly oblong or narrowly obovate, 13–18 × 3–5 mm, pure cream or to pale yellow with pale to dark purplish red tinged, glabrous on both sides, connate to labellum at basal 2/3–4/5, apex often undulate. Stamen 18–25 mm long (to ca. 28 mm long with anther crest stretched); filament absent; anther 8–11 mm long (excluding anther crest), 3.5–4 mm wide, connective tissue cream white to pale yellow, glabrous; anther thecae two, dehiscing throughout entire length, pollen creamy yellow; anther crest ca. 10–12 mm long (to 14 mm long when stretched), pure cream or with purple tinge, glabrous, apex entire. Style filiform, white, glabrous; stigma extends to tip of anther crest, slightly thicker than style, 1–1.5 mm long, funnel-shaped, white, ostiole ciliate. Ovary cylindrical, cream, 5–8 × 3–4 mm, densely pubescent (hair appressed), trilocular; epigynous glands two, 4–7 mm long, narrowly conical, cream-yellow, apex acute. Fruits narrowly ovoid, 2.5–3 × 1.5–1.8 cm, obtusely 3-angled, pilose, pink with red or purple tinge externally, dehiscent along the dorsal suture into three valves when mature; valves 2.5–3 × 1–1.8 cm, scarlet red internally. Seeds 6–9 per locule, oblongoid to spherical, 4–5 × 4–4.5 mm, black, with striae on the surface; aril sac-like, white, covering 1/4 of the seed.

Key to the two subspecies of Zingiber bambusifolium

1a. Labellum and lateral staminodes pure cream, laminae 1.8–3.5 cm wide, rhizome internally beige to peach coloured or dark purplish black, vegetative rhizome units without pseudo-neck.......................................................... Z. bambusifolium subsp. bambusifolium

1b. Labellum and lateral staminodes pale yellow with pale to dark purplish red tinge, laminae 3–5 cm wide, rhizome internally pale yellow, vegetative rhizome units sometimes with a pseudo-neck 1–10 cm long...................... Z. bambusifolium subsp. magenteum