Cornukaempferia argentifolia Boonma & Saensouk, 2021

Cornukaempferia argentifolia Boonma & Saensouk View in CoL , sp. nov. FigS. 1 View Fig & 2 View Fig

Similar to Cornukaempferia larsenii P.Saensouk but differs by its leaves (adaxially silver without markings vs. green with few silvery markings adaxially), bracts (glabrous vs. sparsely hairy), corolla tube (finely hairy vs. glabrous), labellum (obovate with emarginate apex vs. campanuloid with rounded apex) and filaments (finely hairy vs. glabrous).

Type: THAILAND, Phitsanulok province, Chattrakarn district , 420 m, N 17 ̊24'18'', E 100 ̊45'00'', 21.07.2019, T . Boonma 23 (holo KKU!; iso QBG!, BKF!, BK!).

Rhizomatous herbs, up to 20 cm tall. Rhizome subglobose to obovoid, sympodial, slightly aromatic, with 2 layers, both layers yellow (when fresh) and brownish (when dry), 1–1.8 cm diam. Roots fascicle tuberous with fibrous roots; tubers ellipsoid, 1–1.5 mm diam. Cataphylls 1–2, 6–9 cm long, apex acute to slightly mucronate with ciliate margins, sparsely hairy, reddish-brown with white at the base, decaying while the pseudo-stem grows up. Leafsheaths distichous, 7–8 cm long, finely hairy, reddish-brown mixed with green. Ligules membranous, c. 2.5 × 6–7 mm, apex rounded to truncate, glabrous, translucent white. Leaves 2–3; petioles 2.5–4.5 cm long, finely hairy, reddish-brown; lamina ovate, asymmetrical 23–27 × 12–15 cm, apex mucronate, base attenuate, margins entire, translucent red, adaxially silver without marking, midrib lighter silver, sometimes with reddish tinge at midrib, clearly embossed veins, abaxially surface red, both surfaces pubescent. Inflorescence terminal. Peduncles very short, less than 1 cm long. Bract lanceolate, 4.5–5 × c. 1 cm, apex acute, glabrous. Flowers 2 or 3 per inflorescence, c. 4.7 cm long; calyx tubular, 3.3–3.5 cm long, apex bi-lobed with the deepest incision c. 1.5 cm, sparsely hairy, translucent white to pale yellow with red tinge; corolla tube 2.9–3.2 × 0.23–0.25 cm diam., finely hairy, white to pale yellowish-white; dorsal corolla lobe lanceolate, c. 3.4 × 1.1 cm, apex mucronate with slightly hooded, glabrous on both surfaces, yellow with red tinge or yellow with red apex; lateral corolla lobes 2, lanceolate, c. 3 × 0.7 cm, apex acute, glabrous on both surfaces, yellow with red tinge. Staminodes narrowly obovate, c. 2.5 × 1 cm, apex rounded to obtuse, glabrous, yellowish orange gradually fade to pale yellow at base. Labellum obovate, 3.4–3.6 × 2.6–2.8 cm, apex emarginate (incision 5–6 mm), with finely undulate margins, glabrous on both surfaces, upper surface yellowish orange gradually fade to pale yellow at the base with red veins from base to half of the length, lower surface yellowish orange gradually fade to pale yellow without red veins. Stamen 22.8–23.2 mm long; filament c. 3.8 × 2 mm, pale yellowish white, finely hairy; anther 2.8–3 × 0.2–0.3 cm, yellow, opening longitudinally, connective produced into a long, narrow, forwards curved crest, pubescent. Epigynous glands 2, c. 4 mm long, c. 0.6 mm diam., yellow, apex blunt. Ovary ellipsoid-cylindrical, c. 3.6 mm long, c. 4.2 mm diam., pubescent; style white, glabrous; stigma pale yellow, c. 0.7 mm long, c. 0.7 mm × c. 1.4 mm wide, flatten-inverted cone, ciliate. Fruits not seen.

Common name: “ Hazy ” in reference to its silver leaves.

Flowering & fruiting: Flowering from July to September. Flowers open in the morning and last a single day. Leafy shoot emerging in May and dormancy begins in November. Fruiting not observed.

Habitat: Occurring at elevations of 420 meters above sea level, growing in sandy loam soil, moist and close to the watercourse in a deciduous forest.

Distribution: Hitherto endemic to northern Thailand ( Fig. 3 View Fig ).

Etymology: The specific epithet “ argentifolia ” is derived from two Latin words, “ argenti ” meaning “ silver ” and “ folia ” meaning “ leaves ” and refers to its silvery leaves.

Specimens examined: THAILAND, [cultivated] Nakhon Nayok province, Ban Na district, 53 M. 5 Ban Mai village, Phikun Ok , 21.07.2019, T. Boonma 231 (Brio Garden) .

Conservation status: Villagers who live close to the locality report that C. argentifolia argentifolia has been continuously exploited and removed from its habitat for many years. According to our survey since 2018, we found only one locality with mature individuals of less than 1,000. The living plants of this species were also sold in online media and exported overseas too. Due to its popularity, and market demand this species was continuously smuggled out of the forest, such that it is prone to be negatively affected by human activities more than by natural droughts within a very short time and has an uncertain future. However, further fieldwork is needed to assess changes in population distribution and abundance of this taxa. According to IUCN Criteria, ( IUCN, 2019), the species falls under the category Data Deficient ( DD).

Notes: The coloured silver leaves of C. argentifolia makes it easily distinguishable from other species in the genus. It is mostly similar to C. larsenii in having equally sized epigynous glands ( 4 mm long), glabrous staminodes, and labellum on both surfaces but differs in having leaves adaxially silver above and reddish below, glabrous bracts, finely hairy corolla tube, obovate labellum, finely hairy filaments, bi-lobed calyx apex, and a yellow rhizome with yellow core. While C. larsenii has green leaves with few silvery markings above, sparsely hairy bracts, glabrous corolla tube, campanuloid labellum, glabrous filaments, tridentate calyx apex, and a yellowish white rhizome with yellow core. Cornukaempferia argentifolia is also similar to C. kamolwaniae , but can be readily distinguished by its silver coloured leaves. A morphological comparison of C. argentifolia and its allied species is given in Table 1, and a key to the species of Cornukaempferia is also provided for facilitating their identification.