Curcuma fimbriata Škorničk. & Soonthornk., 2021

1. Curcuma fimbriata Škorničk. & Soonthornk. View in CoL , sp. nov. (subg. Hitcheniopsis) — Fig. 1 View Fig

Similar to Curcuma prasina Škorničk. by its ecomate inflorescence composed of green fertile bracts alone, but readily distinguished by cincinni of 10–12 flowers at the base of the inflorescence, white staminodes, white labellum with pale yellow patch in the basal half, distally pale purple with prominently fimbriate margin (vs cincinni composed of 4 or 5 flowers at the base of the inflorescence, pale to dark purple staminodes, pale to dark purple labellum with entire margins and with a bright yellow and swollen median line extending to 2/3 of the labellum in C. prasina ). — Type: Sutthinut Soonthornkalump Sutt-210 (holo QBG, including flowers in spirit as part of a single specimen; iso BK, SING, both including flowers preserved in spirit as part of a single specimen), Thailand, Loei Province, Pha Khao District, Pha Khao Subdistrict , 300 m, 18 Sept. 2019, flowering .

Etymology. The specific epithet is derived from Latin fimbriatus = fimbriate, and refers to the margin of the labellum, which readily distinguishes this species from all other species in subg. Hitcheniopsis.

Perennial rhizomatous herb, 36–100 cm tall. Rhizome ovoid, 1.2–3.4 by 0.9–2 cm, occasionally with lateral branches 1–1.2 by 0.5–0.6 cm, externally yellowish white (young rhizomes) to pale brown, covered with rusty coloured and decayed scales, internally cream white, weakly aromatic and with slightly sweet taste; root tubers globular to ovoid, 1.3–2.4 by 1.2–2 cm, externally light brown, internally white. Leafy shoot with 2 or 3 leaves at anthesis; pseudostem to 80 cm long, composed of 1 or 2 leafless sheaths and 2 or 3 leaf-bearing sheaths, all plain green, glabrous; ligule up to 4.3 mm long, bilobed, hyaline, greenish white, semi-translucent, glabrous except sometimes for a few hairs c. 0.1 mm long on upper margin; petiole 17–58 cm long, canaliculate, green, glabrous; lamina elliptic, 16–36 by 6–17 cm, adaxially dark green, abaxially somewhat paler, glabrous on both sides, midrib green, margin hyaline, c. 0.1 mm wide, glabrous, base obtuse to slightly oblique, apex acuminate to narrowly acuminate. Inflorescence central; peduncle exceeding pseudostem by (0–) 5–15 cm, light green (on exposed part), glabrous; thyrse 4–10.5 by 1.5–3 cm, composed of 8–18 fertile bracts, coma bracts absent; bracts broadly obovate, c. 2.5 by 2.5 cm, connate in basal 1/2–2/3, light green at base, midgreen to dark green distally, glabrous on both sides, apex obtuse to broadly acute, strongly reflexed; cincinni with up to 12 flowers at the most basal bracts, the number gradually decreasing upwards; bracteoles triangular to elliptic, 2.5–8 by 2–5 mm wide at base (outer ones largest), hyaline, semi-translucent white, glabrous, apex slightly concave. Flowers 2–2.6 cm long, exserted from bracts; calyx 4 – 5 mm long, tridentate, with unilateral incision 2–2.5 mm, teeth 0.7–1 mm long with blunt apex, semi-translucent white, glabrous; floral tube 1.5–1.8 cm long, narrowly cylindrical at base, slightly widening distally, externally white, glabrous, internally white and glabrous, distally (near throat) pale yellow with two bright yellow spots on adaxial part, pale purple abaxially, puberulous in distal 1/3; dorsal corolla lobe ovate, 5.5–6 by c. 4 mm, white, glabrous, apex hooded; lateral corolla lobes 4–4.5 by 3–3.5 mm wide at base, ovate to bluntly triangular with obtuse reflexed apex, white, glabrous; labellum 6.5–8 by 4.5–5 mm, obovate with obscurely bifid apex (incision c. 2 mm long), white with pale yellow median band composed of two swollen central lines extending from base of labellum to about 1/2–2/3 towards apex, basally hairy, sides and apical 1/3 pale purple to purple, glabrous, with prominently fimbriate margin, fimbriae c. 1.5 mm long, curly; lateral staminodes narrowly elliptic, 6–6.5 by 1.5–2 mm, apex sometimes with 1 or 2 fimbriae, white (sometimes pale yellow at base) with semi-translucent veins, glabrous on both sides; stamen 4.5–5 mm long; filament 1.5–2.5 mm long, c. 1.5 mm broad at base, 0.6–0.8 mm at the point of attachment, pale purple, glabrous; anther spurless, ovate 2.5–3 mm long (including crest), c. 1.3 mm wide at base, connective tissue white to cream-white, with glandular hairs on sides; anther crest present, obtuse, c. 1 by 1.2 mm wide at base, white; anther thecae c. 1.5 mm long, dehiscing along entire length, white, pollen white; epigynous glands absent; style white, glabrous; stigma unequally funnel-shaped (dorsally significantly side longer), dorso-ventrally compressed, c. 1.3 by 1.1 mm, white; ostiole with smooth to finely irregularly denticulate margin (no hairs), facing forward; ovary globose to ovoid, 1–1.5 by c. 1 mm, trilocular, cream white, glabrous, placentation axile. Fruit a globular capsule, 0.9–1.2 cm diam (almost ripe) cream white, glabrous, dehiscing irregularly, containing 5–15 seeds (most well-developed, some aborted); seeds irregularly obovoid, 3–4 mm long, light brown (almost ripe), shiny, enclosed in translucent white, laciniate aril.

Distribution — Curcuma fimbriata is known from the west of the Phetchabun mountain range. It occurs in four provinces in northeastern Thailand, namely Loei, Chaiyaphum, Phetchabun and Nong Bua Lam Phu.

Habitat & Ecology — Lowland deciduous dipterocarp forests and bamboo forests, and limestone hills, at 250– 400 m elevation. Flowering starts in the rainy season and lasts from July to September. Dormancy begins in early December. Flowers open in the morning and last a single day.

Conservation status — Five locations are known in Loei province, and two locations from Chaiyaphum, and one from Phetchabun and Nong Bua Lam Phu provinces. Of these, presence in Loei and Chaiyaphum is supported by existing herbarium specimens, while records in the latter two are based on photographic evidence. The Extent of Occurrence ( EOO) was calculated from all records and is estimated at 3 844 km 2, and AOO = 32 km 2. Little is known about the size and extent of the populations. One small population is found in an agricultural area, but at least some are located within legally protected areas (national parks or forest reserves). However , the species is occasionally collected from the wild for sale as an ornamental which causes some impact on the number of mature individuals in populations in unprotected areas. We therefore propose to treat this species provisionally as Vulnerable ( VU B1 ab(iii, v), B2 ab(iii, v)) .

Vernacular names and Uses — Cho morakot Mueang Loei ( ช่อมรกตเมืองเลย) = Emerald flower of Loei. No uses have been reported, except occasional sale of the plant as an ornamental in local markets.

Other specimens examined. THAILAND, Loei Province, Pha Khao District, Non Po Daeng Subdistrict, disturbed bamboo and dipterocarp forest, 400 m elevation, 18 Sept.2019,flowering, Thanaphand Namkanya Namkanya -188 ( BK);Phu Kradung, near the foothill quest house (RS-4), 280 m elevation, 27 Aug. 1988, flowering, M. N. Tamura T-60438 ( BKF) ; Chaiyaphum Province, Thung Lui Lai, N16°31'26" E101°50'06", 27 July 1999, flowering, C. Ngamriabsakul 59 ( BKF, E [ E00097671 -herbarium specimen; E00830346 -preserved in liquid]); ibidem, collected from living collection of RBGE 19991191 , 24 Aug. 2005, J. Škorničková 73328 ( E [ E00211374 -herbarium specimen, E00211514 -preserved in liquid]); Khon San District , Thung Lui , Lai , collected from living collections at BK, 29 June 1999, P. Triboun 612(l) (BK-preserved in liquid); Kaeng Kho District , 7 Aug. 2003, flowering, W. Somprasong s.n. ( BK [BKs00946-preserved in liquid]) GoogleMaps .

Additional photographic material. THAILAND, Phetchabun, Nam Nao National Park , 2013, (provided by Dr. Sunisa Sangvirotjanapat) ; Nong Bua Lam Phu Province, Na Wang District , Na Lao subdistrict, 2019 (provided by Thanaphand Namkanya) .