Curcuma ungmensis M.Sabu, Hareesh and P.Tiatemsu, 2024

Sabu, Mamiyil, Hareesh, Vadakkoot Sankaran & Tiatemsu, Punatemjen, 2024, Curcuma ungmensis (Zingiberaceae): a new species from Nagaland, North-East India, Phytotaxa 663 (2), pp. 90-94 : 91-93

Curcuma ungmensis M.Sabu, Hareesh and P.Tiatemsu sp. nov. ( Fig. 1 )

C. ungmensis is similar to C. inodora Blatter (1931: 357) in the general habit, white bracts with purple tinge at the tip, purple corolla lobes and yellow flowers but differs from the latter by its large branched rhizome (vs. small unbranched, ovoid), and flowers up to 5.9 cm long (vs. up to 4 cm long).

Type:— INDIA. Nagaland: Mokokchung district, three kms towards Tuensang, Ungma Village , 26° 18' 15'' N, 94° 30' 31'' E, 1173 m, 03 September 2023, M. Sabu, V. S. Hareesh & P.Tiatemsu 19599 MBGH (holotype MBGH; isotype ASSAM) .

Rhizomatous herb, 65–90 cm tall. Rhizome with lateral branches, 12–13.5 × 4–5 cm, deeply buried in the ground, older rhizomes brown externally, younger ones white, glabrous, sheathed by papery scales, white or pale yellow internally, faintly aromatic, fleshy roots end in ovoid root tubers. Leafy shoot 35–80 cm long, leaves 2–3 in number. Pseudostem 10–13 cm long, deeply buried in the soil, formed by leaf sheaths and 2–3 sheathing bracts; ligule absent or very short; petiole 25–30 cm long, green, glabrous; lamina ovate-elliptical, 38–42 × 16–18 cm, apex acuminate, margin hyaline, translucent white, shortly hairy, base acute to acuminate, adaxially light green, prominent veins quite closely arranged, c. 5 mm apart, abaxially pale green, puberulent, midrib green, glabrous. Inflorescence central. Peduncle 11–23 × 0.8–1.0 cm, white, glabrous, hidden in pseudostem. Spike 13–19 × 4–5 cm, 16–23 fertile bracts and 10–13 coma bracts. Fertile bracts ovate-elliptical, 3–3.5 × 2.7–3 cm, lower half fused with the axis, white with light purple color towards tip, glabrous on both surfaces, slightly acuminate at tip. Coma bracts more linear than fertile ones, obovatelanceolate, 4–4.2 × 1.5–1.6 cm, white with purple tinge towards margin and tip, glabrous, tip slightly acute. Cincinnus 3-flowered. Bracteole single per flower, 1.2–2 × 0.5–0.7 cm, hyaline, translucent white, glabrous, apex mucronate. Flowers 5.5–5.9 × 1.4–1.6 cm, almost double the size of floral bracts. Calyx 10–11 mm long, 3-toothed, 1–2 mm deep, white, pubescent outside. Corolla tube 4–4.3 cm long, yellow, sometimes tinged with pink or yellow towards lobes, glabrous; dorsal corolla lobe broadly triangular, 1.8–2 × 1–1.2 cm, mucronate at apex, mucro 3–4 mm long, white with a pink tinge towards tip, glabrous; lateral corolla lobes 1.1–1.2 × 0.8–0.9 cm, glabrous, purple, apex slightly acute. Lateral staminodes oblong-lanceolate, apex obtuse, 1.6–1.8 × 0.6–0.7 cm, usually pale yellow with white towards base. Labellum 2.4–2.5 × 1.3–1.5 cm, tip emarginate, split 4–5 mm deep, deep yellow band at middle, light yellow towards base and margins. Anther spurred, anther thecae whitish, 6–7 mm long; filament 6–8 mm long, yellow, 3–4 mm broad at base, c. 2 mm broad at upper part; spur 3–3.5 mm long, white, pointing forward, glabrous. Ovary trilocular, 4–5 × 2.5–3 mm, densely hairy; stigma appressed within lobes, 1–2 mm long, white, mouth hairy. Epigynous glands 2, 2.5–3 × 0.5–0.7 mm, yellow. Fruit not seen.

Flowering:—Flowering starts in the rainy season of August and lasts up to October and the plants enter dormancy in January. Flowers open in the morning and last a single day. Inflorescence centrally amidst leaves.

Distribution, conservation and biotic association:—The plant was found along roadside in the Ungma Village of Mokokchung district of Nagaland, ie., about three kms. from the Mokokchung Town towards Tuensang. So far known only from the type locality and adjacent areas on east facing slopes. Preliminary observations have shown that more than 1000 individuals are present in this locality. This species faces a severe threat from various human activities such as road widening, construction of buildings, urbanization and natural calamities. The dominant tree species in that area is Quercus serrata Murray (1784: 858) with occasional mix of Urena lobata Linnaeus (1753: 692) , Kaempferia rotunda Linnaeus (1753: 3) , Bidens pilosa Linnaeus (1753: 832) , Colocasia sp. , etc. forms a dominant ground vegetation.

Uses:—The attractive colour of the inflorescence makes this a good candidate as cut flower. It can be introduced in gardens as an ornamental plant for ground cover after proper domestication.

Etymology:—The specific epithet ‘ ungmensis ’ refers to the name of the village Ungma where the type materials were collected.

Notes:—The new species C. ungmensis is most allied to C. inodora Blatter (1931: 357) , a species commonly distributed along the Western Ghats in Goa, Maharashtra and Karnataka. The most prominent difference between these two species lies in the flowers and rhizomes. The rhizome in C. ungmensis is branched and much larger against small, unbranched and conical rhizome in the latter. A detailed comparison of these two species are given in Table 1.

Figures

FIGURE 1. Curcuma ungmensis sp. nov. A. Habit; B. Inflorescence; C. Rhizome; D. C.S. of rhizome; E. Fertile bract; F. Coma bract; G. Bracteole; H. Flower; I. Calyx; J. Dorsal corolla lobe; K1 & K2. Lateral corolla lobes; L1 & L2. Lateral staminodes; M. Labellum; N. Anther lateral-view; O. Anther front-view; P. Ovary with epigynous glands; Q. Ovary. (Photos by M. Sabu & V.S. Hareesh).