Wurfbainia ellipticarpa Kaewsri, 2022

Kaewsri, W. & Sangvirotjanapat, S., 2022, SIX NEW SPECIES OF WURFBAINIA (ZINGIBERACEAE) FROM THAILAND, Edinburgh Journal of Botany 79 (369), pp. 1-23 : 3-6

1. Wurfbainia ellipticarpa Kaewsri , sp. nov.

Similar to Wurfbainia villosa (Lour.) Škorničk. & A.D.Poulsen but differs in its narrower labellum (c. 1 cm vs c. 1.5 cm), inflorescence lax (vs congested) and fruit ellipsoid (vs globose to ovoid) ( Table 1 ).

– Type: Thailand, Kanchanaburi, Thong Pha Phum National Park , c. 800 m altitude, 25 v 2004, Kaewsri 024 (holotype BKF!; isotypes BK!, E!). Figures 1 , 2 .

Rhizomatous herb, long creeping, leafy shoot slender, c. 1.5 m tall. Leaf sheaths glabrous, pale green; ligule apex bilobed or rounded, 5–13 mm long, chartaceous; blades c.25, oblong, 18–35 × 1.5–5.5 cm, base attenuate, apex acuminate, 2–5 cm long, glabrous on both sides, sessile. Inflorescence lax, arising from rhizome, obovate, 5–6 × 3–5 cm; peduncle 6–9 cm long; peduncular bracts ovate to oblong, c.1.2 × 0.6 cm, apex rounded, margin entire, brown, glabrous to sparsely pubescent; rachis slightly curved; fertile bracts hooded, ovate to oblong, c.2.5 × 0.7 cm, apex acuminate or mucronate, pale brown, brown pubescent, soon decaying, submembranous; bracteoles tubular, c.1.4 × 0.4 cm including ovary, apex bilobed, slit c. 6 mm on one side, brown, fine pubescent above, membranous. Flower c. 3 cm long, creamy white; pedicel 1–2 mm long, ovary cylindrical to subglobose, c.3 × 2 mm, glabrous; style c. 2.8 cm long, creamy white, pubescent; stigma small bulbous, margin glabrous; epigynous glands blunt, c.1 × 3 mm; calyx tubular, c. 1.5 cm long, apex trilobed, creamy white, glabrous; floral tube 1.3 cm long, creamy white, glabrous; dorsal corolla lobe broadly oblong, c.1.3 × 0.6 cm, apex obtuse, creamy white, glabrous; lateral corolla lobes oblong, c.1.3 × 0.5 cm, apex obtuse, creamy white, glabrous; lateral staminodes absent; labellum hooded, ovate, c.1.6 × 1 cm, base cuneate, apex bilobed and reflexed, white with pale yellow band along the centre and broader at apex, pale red veins on each side of the band, glabrous; stamen: filament c. 6 mm long, ribbon-like; anther c.6 × 3 mm, glabrous, dehiscing longitudinally; anther crest trilobed, white, central lobe c.1 × 1 mm, apex rounded, reflexed, lateral lobes c. 0.5 mm long, small auriculate, erect. Fruit 5–8 per infructescence, ellipsoid, c.2 × 1.2 cm, covered with slender spines, pinkish red and turning dark brown when mature; stalk 5–7 mm long; seeds angular, c. 1–2 mm in diameter, covered with white aril.

Phenology. Flowering and fruiting between April and September.

Distribution. Known only from the type locality ( Figure 3 ).

Habitat. Thrives in dry evergreen forest in light gaps at 800 m altitude.

Etymology. The specific epithet refers to the ellipsoid fruit.

Proposed IUCN conservation category. Critically Endangered (CR). This species is found only in Thong Pha Phum National Park, Kanchanaburi Province. Two populations were located during fieldwork in 2004. The total number of individuals was below 50. Although they were in good condition and subject to no major threats, the restricted numbers of populations and individuals must be taken into consideration. Wurfbainia ellipticarpa is therefore assessed as Critically Endangered according to criterion D.

Figures

Figure 1. Wurfbainia ellipticarpa Kaewsri, sp. nov. A, Rhizome and inflorescence; B, leaf; C, bract; D, bracteole; E, calyx; F, stigma; G, flower (dissected); H, infructescence. Drawn from Kaewsri 024 by W. Kaewsri.

Figure 2. Wurfbainia ellipticarpa Kaewsri, sp. nov. A, Ligule; B, leaves; C, inflorescence; D, mature infructescence; E, young infructescence. All photographs of the type collection (Kaewsri 024), taken by W. Kaewsri.

Figure 3. Species distribution map. The unbroken-line box indicates the localities of Wurfbainia ellipticarpa, W. globosa and W. longiflora. The dashed-line box indicates the localities of Wurfbainia geostachyoides, W. parviflora and W. yingyongii.