Kaempferia calcicola Noppornch., 2024

Nopporncharoenkul, Nattapon, Sukseansri, Wiphada, Nopun, Possathorn, Meewasana, Jiraporn, Jenjittikul, Thaya, Chuenboonngarm, Ngarmnij, Viboonjun, Unchera & Umpunjun, Puangpaka, 2024, Cytotaxonomy of Kaempferia subg. Protanthium (Zingiberaceae) supports a new limestone species endemic to Thailand, Willdenowia 54, pp. 121-149 : 136-139

Kaempferia calcicola Noppornch. , sp. nov. – Fig. 6 , 7 .

Holotype: Thailand, Khon Kaen province, Phu Pha Man district, Na Fai , 347 m elevation, 27 Apr 2023 (in flower), N. Nopporncharoenkul NNSB-903 ( QBG including flowers preserved in spirit as part of a single specimen; isotypes: BK, BKF, SING, SLR).

Diagnosis — Kaempferia calcicola Noppornch. is similar to K. takensis Boonma & Seansouk in overall habit, inflorescence and floral plane, but differs by anther crest obreniform, broadly ovate, obovate to obdeltoid (vs anther crest oblong to ovate in K. takensis ) with irregular undulate to crenate apex (vs bilobed to irregularly tridentate apex, usually with 2–3 small teeth between lobes in K. takensis ) and labellum with an incision c. 3/5 of its length (vs labellum with an incision more than 2/3 of its length in K. takensis ). It is also similar to K. lopburiensis Picheans. in inflorescence, floral plane and flower colour, but differs by prominent pseudostem upright above ground (vs pseudostem short and completely embedded in soil in K. lopburiensis ), leaf blades elliptic, elliptic-oblong to lanceolate-oblong and longer petiole 3–18(–30) cm long (vs leaf blades suborbicular to ovate, adpressed on ground and subsessile petiole in K. lopburiensis ).

Description — Rhizomatous herb, up to 75 cm tall. Rhizome ovoid to subglobose, 1.5–2.5(–3) cm long, 1–1.5(–2.3) cm in diam., brown externally, cream white internally, with short fascicled storage roots and terminal tubers; root stalk swollen, 0.4–1.8(–3.5) cm long, 0.2– 0.3 cm in diam.; tubers fusiform to narrowly fusiform, 2–5.8(–9.5) cm long, 0.6–1.5 cm in diam. Leafy shoot with (4–)6–8 leaves; pseudostem upright, up to 25 cm tall; bladeless sheaths 2–3, up to 10 cm long, plain green to dull reddish, apex obtuse to mucronate, mucro c. 1 mm long, glabrous to sparsely villous; leaf sheaths plain green to dull reddish, glabrous to sparsely villous; ligule bilobed, partly overlapping when young, lobes rounded to triangular with rounded to obtuse apex, 4–7(–12) mm long, semi-translucent, white to reddish, glabrous to sparsely villous; petiole 3–18(–30) cm long (lower leaves shorter), plain green, glabrous to sparsely villous; leaf blade elliptic (usually found in first two leaves), elliptic-oblong to lanceolate-oblong, 20–35(–40) × (5–) 6.5–15 cm, adaxially plain green to grey-green, sometimes with 1–2 layers of white to silvery patches arranged parallel along leaf edges (between midrib and both sides of edges), glabrous, abaxially plain green, sometimes deep purplish red, sparsely villous, base attenuate, obtuse to rounded, slightly oblique, margin entire, slightly undulate, apex mucronate, mucro c. 1 mm long. Inflorescence lateral, emerging from rhizome before leafy shoot, sheathing bracts 2, deltoid-ovate, 0.5–0.8 × 0.5–0.8 cm, apex mucronate to acute with densely villous, light green to reddish sparsely villous; peduncle (1.5–)3.8–7(–10) cm long, glabrous to sparsely villous; raceme fusiformovoid, 4–5.5 cm long, 0.8–2 cm in diam., composed of up to 30 bracts each supporting a single flower; bracts deltoid-ovate to lanceolate-ovate, 1.5–5 × 0.6–4 cm (outer bracts larger), apex mucronate to acute with densely villous, light green, reddish to purplish red, sparsely villous; bracteoles lanceolate-ovate, 1.5–2.8 × 0.6–1.2 cm, irregularly bifid with an incision 1–1.5 mm, apex mucronate to acute, hyaline, sparsely villous. Flowers 8–11 cm long, diurnal anthesis; floral plane flat type, consisting of horizontal to slightly arcuate lateral staminodes and labellum, which are laid in same plane and parallel to ground; calyx 3.5–5.8(–6.5) cm long, 0.4–0.6 cm in diam., with unilateral incision 1–1.8 cm long from apex, apex truncate to shallowly trilobed-crenate with 2 mucroteeth, semi-translucent light green, sometimes with several reddish spots, sometimes densely villous at apex; floral tube 5.5–8(–9) cm long, 2–3 mm in diam., narrowly cylindric at base above ovary, narrowly funnel-shaped distally, white, glabrous externally and internally; dorsal corolla lobe lanceolate-oblong, 2.4–3.8 × (0.5–) 0.6–0.8 cm, apex hooded, mucronate, mucro 2–3 mm long, concave, sometimes cochleate, white, glabrous; lateral corolla lobes lanceolate-oblong, 2–3.5 × 0.5–0.6(–0.7) cm, apex mucronate, mucro c. 1 mm long, concave, sometimes arcuate, white, glabrous; lateral staminodes obovate to elliptic-oblong, 2.6–3.7 × 1.3–2 cm, apex acute, obtuse to rounded, sometimes crenate to incised at apex, arcuate, white to pale light pink; labellum obdeltoid to obovate, 2.4–3.8 × (2–) 2.4–3.2 cm, bilobed, with an incision c. 3/5 of labellum length, base slightly involute, loosely enclosing anther, lobes obovate, elliptic-oblong to suborbicular, 1.6–2.3 × 1.2–2 cm, apex acute, obtuse to obcordate, sometimes crenate to incised at apex, partly overlapping, arcuate, white to pale light pink with central white to cream white patch basally surrounded by two light pink to light purple stripes from base toward centre of lobes; stamen 7–9 mm long, subsessile; filament short, up to 1 mm long; anther 6–8 mm long including nearly perpendicular anther crest, connective tissue white, glabrous; anther crest extends backward with nearly perpendicular to anther, obreniform, broadly ovate, obovate to obdeltoid, 5–7.5(–11) × (6–) 8–10 mm, apex irregular undulate to crenate; anther thecae 3–4(–5) × 1–1.2 mm, cream white, dehiscing along their entire length, pollen white to cream white; ovary cylindric, (4–) 5–6 mm long, 2–3(–4) mm in diam., trilocular, cream white, glabrous, ovules numerous, placentation axile; epigynous glands 2, subulate, 6–7 mm long, cream white; style 5.8–8.5 cm long; stigma crateriform, 1.5–1.8 × 0.5 mm, ostiole ciliate. Fruit ovoid to subglobose, 1.8–2 cm long, 1–1.4 cm in diam., trilocular, light greenish yellow to purplish red, usually with several reddish to purplish red spots, glabrous, rarely sparsely villous at apex, with 9–22 seeds; seeds subglobose, prolate, obovoid to ovoid, 4.2–5.8 mm long, 2.6–3.5(–4.5) mm in diam., yellowish cream to light brown with reddish spots, enclosed in a fleshy semi-translucent white, laciniate aril.

Chromosome number — 2 n = 22.

Phenology — Flowering period starts in late March and lasts until April (diurnal anthesis). Fruit and seeds mature in April to May. Leafy shoots usually emerge in May. The plants enter dormancy in November.

Distribution and ecology — Kaempferia calcicola is distributed in Phu Pha Man District, Khon Kaen province, NE Thailand. It grows on the top of limestone hills or cliffs, in the pockets filled with loamy soil and covered with leaf debris, full sun to partial shaded, usually with Euphorbia lacei Craib and Dracaena sp. , at 340–355 m elevation.

Conservation status — The species is strictly endemic to the limestone hills in Phu Pha Man District of Khon Kaen province. The EOO and AOO, which are considered from the overall area of limestone hills in the type locality and surrounding areas observed in Google Earth (https://www.google.com/earth/), are estimated to be less than 50 km 2 and 4 km 2 respectively, with approximately 200 mature individuals. Currently , the suitable habitats of the species, especially the limestone area in Khon Kaen and adjacent provinces in NE Thailand, are severely fragmented geographically and continue to decline in the area due to quarrying for the construction industry (limestone and cement materials). Moreover , the type locality is not under any legal protection while the plants have been collected to sell as a rare, ornamental plant. The current information on the EOO and AOO leads us to propose that Kaempferia calcicola be treated as Critically Endangered ( CR) B1 ab(i,iii,v)+B2ab(ii,iii,v) in accordance with guidelines to the IUCN Red List Categories and Criteria, version 15.1 ( IUCN Standards and Petitions Subcommittee 2022).

Etymology — The specific epithet calcicola refers to the limestone habitat of the species.

Vernacular name — We propose the common name ดอกดินเขาหินปูน (Dok Din Khao Hin Poon) in Thai language. “Dok Din” is the flower which occurs on the ground (well-known as earth flower), and “Khao Hin Poon” means limestone hill. This common name refers to the earth flowers occur on the limestone hill.

Additional specimens examined (paratypes) — Thailand, Khon Kaen province, Phu Pha Man district , 350 m elevation, 29 Aug 2023, N. Nopporncharoenkul NNSB-944 ( QBG, SLR); ibid., 340 m elevation, 6 Apr 2024, N. Nopporncharoenkul NNSB-969 ( QBG, SLR).

Remarks — The leafy shoot of Kaempferia calcicola consists of a remarkable upright pseudostem, a long petiole and elliptic, elliptic-oblong to lanceolate-oblong leaf blades, which are extremely similar to those of K. rotunda morphologically. The differences of both species can be found mainly in flower morphology ( Table 2 ; Fig. 2 ). The flower of K. calcicola is the flat type floral plane ( Nopporncharoenkul & al. 2021), consisting of lateral staminodes and labellum horizontal to slightly arcuate, which laid in the same plane and parallel to the ground, and represents an obreniform, broadly ovate, obovate to obdeltoid anther crest with an irregular undulate to crenate apex, the anther crest extends backward and positioned nearly perpendicular (c. 90 degree) to the anther connective, a labellum with an incision c. 3/5 of its length, a labellum base involute loosely enclosing the anther, and an extremely short filament. In contrast, the flower of K. rotunda is the perpendicular type consisting of upright to slightly arcuate lateral staminodes and a deflexed in distal half labellum ( Nopporncharoenkul & al. 2021) and represents an oblong to ovate anther crest with a bilobed apex, usually with 2–3 small teeth between lobes, the anther crest extends upward with an angle nearly of 180 degree to the connective, a labellum with an incision c. 1/2 of its length, a flat labellum base, and a prominent, flat filament. However, the flowers and inflorescences of K. calcicola are entirely similar to those of K. lopburiensis and K. takensis . The distinct characteristics between K. calcicola and K. lopburiensis are found in the leafy shoots ( Table 2 ). Kaempferia lopburiensis is easily distinguished from K. calcicola by having a short pseudostem completely embedded in the soil, suborbicular to ovate leaf blades flat on the ground with very short petioles, and a deeply bilobed labellum with an incision more than 2/3 of its length. Kaempferia takensis can also be differentiated from K. calcicola by having an oblong to ovate anther crest with a bilobed to irregularly tridentate apex, usually with 2–3 small teeth between the lobes and a deeply bilobed labellum with an incision more than 2/3 of its length. Geographically, K. calcicola occurs only on the tops of limestone hills or cliffs without a coexistence of any Kaempferia species. We found only K. udonensis in deciduous forest with bamboos in the foothills, without the occurrence of K. calcicola sympatrically.

Figures

Fig. 6 (right page). Kaempferia calcicola. – A: habitat with plants in flowering period; B: plant habit in flowering period; C: inflorescences and flowers in top view; D: habitat with plants in rainy season; E. plant habit in rainy season. – All photographs taken at type locality: Thailand, Khon Kaen Province, Phu Pha Man District, A: 27 Apr 2023; B, C: 6 Apr 2024; D, E: 29 Aug 2023, by N. Nopporncharoenkul.

Fig. 7 (left page). Kaempferia calcicola – A: Inflorescence and rhizome; B: habit; C: pseudostem with ligules; D: rhizome with fascicled storage roots and numerous fusiform tubers; E: flower in front and side view; F: calyx (inset: detail of calyx apex); G: floral tube with ovary and stamen in front and side view; H: flower dissection (dc: dorsal corolla lobe; l: labellum; lc: lateral corolla lobe; ls: lateral staminode); I: detail of stamens and anther crests in front and side view; J: detail of pistil (from left to right: pistil; stigma and style in front and side view; ovary with epigynous glands); K: fruit; L: seeds. – All from Nattapon Nopporncharoenkul NNSB-903 (QBG). – All photographs by N. Nopporncharoenkul.

Fig. 2. Floral morphology of Kaempferia subg. Protanthium in Thailand – A: K. albiflora (NNSB-546); B: K. aurora (NNSB-713); C: K. caespitosa (NNSB-733); D: K. calcicola (NNSB-903); E: K. graminifolia (NNSB-686); F: K. grandifolia (NNSB-519); G: K. jenjittikuliae (NNSB-760); H: K. lopburiensis (NNSB-541); I: K. noctiflora var. noctiflora (NNSB-554); J: K. noctiflora var. thepthepae (NNSB-928); K: K. rotunda (NNSB-534); L: K. simaoensis (NNSB-676); M: K. sipraiana (NNSB-656); N: K. subglobosa (NNSB-749); O: K. takensis (NNSB-697); P: K. udonensis (NNSB-508). – All photographs by N. Nopporncharoenkul.