Wurfbainia yingyongii Kaewsri, 2022

Kaewsri, W. & Sangvirotjanapat, S., 2022, SIX NEW SPECIES OF WURFBAINIA (ZINGIBERACEAE) FROM THAILAND, Edinburgh Journal of Botany 79 (369), pp. 1-23 : 19-22

6. Wurfbainia yingyongii Kaewsri , sp. nov.

Similar to Wurfbainia biflora (Jack) Škorničk. & M.F.Newman but differs in its labellum ovate (vs obovate) and orange middle band on labellum (vs mid-red to dark red band) ( Table 5 ).

– Type: Thailand, Kanchanaburi, Sai Yok National Park , Taodam Forest , primary evergreen forest, 14°16′15.7′′N, 98°44′12.6′′E, 398 m altitude, 25 iv 2003, Kaewsri 001 (holotype BKF!; isotypes BK!, E!). Figures 12 , 13 .

Clump-forming herb, leafy shoot slender, 0.9–1.8 m tall, base swollen, purple when young. Leaf sheaths green; ligule papery, 1–5 mm long, bilobed, sparsely villous; petiole 3–6 mm long, sparsely pubescent; blades (4–)8–16, oblong to broadly elliptic, 10–24(–36) × 5–9 cm, base attenuate or rounded, apex acuminate to obtuse, apex caudate, 1–2 cm long, margin undulate, upper surface glabrous, lower surface densely tomentose. Inflorescence arising from rhizome, conical to obovate, c.3 × 1.5 cm; peduncle c. 1.5 cm long; peduncular bracts ovate to oblong, apex rounded, densely pubescent, leathery; fertile bracts ovate to elliptic, c.1.8 × 0.9 cm, apex mucronate, margin ciliate, outer surface brownish pubescent; bracteoles tubular, c. 1 cm, apex bilobed and shallowly split on one side, outer surface brownish pubescent, margin ciliate. Flower c. 3 cm long, creamy white; ovary subellipsoid, c. 3 mm long, pubescent; style c. 1.3 cm long; stigma cup-shaped, c. 2.5 mm wide, ostiole ciliate; epigynous glands c. 3 mm long; calyx tubular, c. 1.6 cm long, apex trilobed and split to 5 mm on one side, outer surface brown pubescent, margin ciliate; corolla creamy white, tube glabrous, c. 1.7 cm long including ovary, dorsal lobe hooded, broadly oblong to ovate-oblong, c.1.9 × 0.7 cm, apex apiculate, lateral lobes slightly smaller, apex blunt, hooded; lateral staminodes absent; labellum broadly ovate, spreading, c.2.3 × 2 cm, base attenuate, apex obtuse and wrinkled, margin wavy and revolute, white with orange-yellow blotch spreading to apex, reddish lateral stripes from base upwards to middle, 2-grooved near apex, sparsely pubescent at base; stamen: filament c.6 × 2.5 mm, shallowly concave; anther 3–4 × 3 mm, dehiscing lengthwise; anther crest horn-like, trilobed, c.4 × 4 mm, creamy white, central lobe slightly reflexed, apex rounded, lateral lobes smaller, apex acute, spreading. Fruit globose to elliptic, 1.5–1.8 cm in diameter, 2 or 3 per infructescence, densely covered with rigid spines, green when young turning dark red when ripe; seeds not seen.

Phenology. Flowering and fruiting between March and July.

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

Habitat. Dry evergreen forest, under shade of shrubs and trees, c. 400 m altitude.

Etymology. The specific epithet honours Associate Professor Dr Yingyong Paisooksantivatana, who dedicated his life to the study of Amomum sensu lato in Thailand.

Proposed IUCN conservation category. Critically Endangered (CR). This species is found only in Taodam forest, Sai Yok National Park, Kanchanaburi Province. Although it grows in a protected area that is subject to no threats, the population comprises fewer than five mature individuals, which may be destroyed by animal grazing or flooding. Wurfbainia yingyongii is therefore assessed as Critically Endangered according to criterion D.

Additional specimen examined. THAILAND. Kanchanaburi: Sai Yok , 11 v 2010, Kaewsri 138 (BK, BKF) ; Sai Yok , 28 v 2010, Kaewsri 178 (BK, BKF) .

This species is characterised by its white labellum with orange centre and ribbed stripes.

Figures

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.

Figure 12. Wurfbainia yingyongii Kaewsri, sp. nov. A, Pseudostem with leaves; B, ligule; C, inflorescence; D, bract (left) and peduncular bract (right); E, bracteole; F, calyx; G, flower (dissected); H, anther crest; I, labellum; J, pistil; K, infructescence. Drawn from Kaewsri 001 by W. Kaewsri.

Figure 13. Wurfbainia yingyongii Kaewsri, sp. nov. A, Young leafy shoot; B, pseudostem base; C, ligule; D, leaves; E, inflorescence; F, infructescence; G, fruit (cross-section). All photographs of the type collection (Kaewsri 001), taken by W. Kaewsri.