Amomum raoii var. oblongum (V.P. Thomas & M. Sabu) M.Sabu & V.P. Thomas, 2020

Thomas, V. P., Sabu, M., Jayakrishnan, T. & Rajeesh, E. P., 2020, A new species and a new combination of Amomum Roxb. (Zingiberaceae) from Sikkim Himalaya, India, Phytotaxa 430 (1), pp. 46-50 : 48-50

Amomum raoii var. oblongum (V.P. Thomas & M. Sabu) M.Sabu & V.P. Thomas comb. nov.

Basionym :— Amomum kingii var. oblongum V.P. Thomas & M. Sabu (2015:89) .

Type:— INDIA. Sikkim: East Sikkim District, Pangthang, alt. 1890 m, 7 May 2007, V. P. Thomas & V. A. Muhammed Nissar 95501 (holotype CALI!, isotype CAL!).

Rhizome non-stoloniferous, stout, robust, 4–5 cm thick, pale yellow inside, covered with scales; scales coriaceous, glabrous. Leafy shoots 300–350 cm tall, robust, clump forming; sheath ca. 4 cm wide at base, green with pale pink margins, lined with prominent parallel veins, margin membranous, glabrous. Leaves 8–10 per shoot; lamina oblong-lanceolate, 27–120 × 10–25 cm, dark green above, glaucous beneath, base oblique, apex acuminate, glabrous on both surfaces except a layer of hairs near margin beneath; midrib pink, glabrous; veins appressed above; petiole 2.5–4 cm long, green, glabrous. Ligule entire, 1–2 cm long, green tinged with pink, apex acute to rounded, margin ciliate, pubescent inside groove. Inflorescence 25–50 cm long, many flowered, arise from rhizome just below the aerial shoot; peduncle 8–15 cm long. Sheathing bract 6–9 per inflorescence, oblong or oblong-lanceolate, 9–13 × 3.5–5 cm, brown, margin ciliate, connate margins with adjacent bracts, glabrous and rarely puberulous externally. Bract 2.6–3 × 0.5–0.7 cm, membranous, early drying, white, margin ciliate, apex acute to rounded, glabrous. Bracteole non-tubular, represented by rudimentary lanceolate structure, 0.8–1.2 × 0.1–0.2 cm, membranous, white tinged with pink, non-tubular, margin ciliate, glabrous. Flower 5.5–6 cm long, white tinged with yellow, borne singly from each bract. Calyx 3-lobed, c.2.5 × 0.8 cm, membranous, white, a small notch present at tip of each lobe, cleft 0.5–1.2 cm deep, puberulous towards apex externally, glabrous within. Corolla tube c. 9.2 cm long, c. 0.3 cm wide at mouth, white, pubescent externally, pubescent within, densely towards mouth; dorsal corolla lobe oblong, 2.4–2.6 × 1.2–1.4 cm, white, margin rarely distantly ciliate towards base, apex hooded, pubescent externally, glabrous within; lateral corolla lobes oblong, 2.2–2.3 × c. 0.9 cm, pubescent externally, glabrous within. Labellum obovate, 3-lobed, c.3.5 × 2.5 cm, white towards periphery, centre with spreading pink bands from base, red tinged at base, margin crenulate, crumbled, pubescent internally towards lower part. Lateral staminodes ribbon-like, flat, 1.2–1.5 cm long, tapering towards apex, white, lower part red, densely pubescent towards base, glabrous towards apex. Stamen 2.3–2.5 cm long, filament c.0.8 × 0.4 cm, white, pink towards base, pubescent on both surfaces; connective pubescent; crest irregularly lobed, 0.6–0.7 × 0.8–0.9 cm, white, glabrous, puberulous externally; anther thecae oblong, 1.2–1.3 cm long, cream-coloured, base tapering, apex diverging, glabrous; dehiscing throughout their length. Epigynous glands irregularly split, 0.3–0.4 cm long, cream coloured, apex truncate, glabrous. Ovary oblong, 0.8–1.1 × 0.5–0.6 cm, glabrous; pedicel pubescent; locules 3; ovules many on axile placentae; style c. 4.4 cm long, puberulous towards tip; stigma cup-shaped, c. 0.1 cm across, white, mouth ciliate, opening terminal. Infructescence 30–60 cm, many in a spike; peduncle c. 15 cm long; calyx persistent. Capsule oblong or ovate-oblong, smooth walled, no apical depression, 3.8–4.5 × 2.2–2.5 cm, pale pink to white, glabrous, stalk 0.5–0.7 cm long. Seeds many, angular, 0.3–0.6 × 0.3–0.4 cm, brown, aromatic, glabrous, arillate; aril white.

Flowering:—March–May.

Fruiting:—June–August.

Distribution:—Collected only from Pangthang, East Sikkim District of Sikkim.

Ecology:—In shaded places at high elevations of Sikkim Himalaya.

Etymology:—The specific epithet ‘oblongum’ refers to oblong shape of inflorescence and fruits.