Curcuma leonidii Škorničk.

Leong-Škorničková, J. & Trư ờng, Lưu H ồng, 2013, Curcuma leonidii, a new species from southern Vietnam, Phytotaxa 126 (1), pp. 37-42 : 37-39

Curcuma leonidii Škorničk. & LƯu

Similar to Curcuma harmandii Gagnep. (subg. Hitcheniopsis ) in inflorescence consisting of green bracts with no obvious coma, but differs from it by having a more compact inflorescence (vs. more elongated in C. harmandii ), white corolla lobes (vs. greenish), white oblanceolate-spathulate shape of the lateral staminodes (vs. greenish-white nearly linear) and white labellum with rich yellow well-defined median, the sides of the basal half of the median puberulent, patched with red, and nearly plain margin (vs. white labellum with yellow pubescent median bordered around with pink tinge, especially towards the apex, and crisped margin).

Type: — VIETNAM. Bình Phư ớc Province : Bù Gia M ập National Park, Đ ắc Ca stream, 8 May 2012, LƯu Hồng TrƯƠng, Đinh Nh ật Lâm & Võ Huy Sang LUU 807 (holotype SING!, isotypes SGN!, SING!). Figure 1 .

Rhizomatous herbs to 30 cm tall. Rhizomes not branched, irregularly globose, ca 1 × 1 cm, externally light brown, internally light orange, root tubers present, placed 2–5 cm from rhizome. Pseudostems c. 3–5 cm (but fully opens up when the inflorescence emerges), composed of 1–2 leafless sheaths and 2–4 leaf sheaths; ligules 1–2 mm, bilobed, hyaline, with a few stipitate hairs. Leafy shoots with 2–4 leaves; petiole 3–8 cm (in dried specimens up to 7 cm), green, canaliculate, externally puberulous; lamina elliptic-lanceolate, up to 22.0 × 6.5 cm (in dried specimens up to 18.5 × 5.8 cm), abaxially green, glabrous with sparse hairs along the midrib, adaxially lighter green, glabrous with sparse hairs along the midrib, base obtuse, slightly oblique, apex attenuate with uppermost tip densely hairy. Inflorescence central, peduncle 2–5 cm, hidden between the leaf sheaths; spike 4–5 × c. 2–3 cm, coma absent. Bracts rhomboid, (1–)2–8(–10) per inflorescence, lower bracts ca 4.0–5.0 × 2.0– 2.5 cm (in dried specimens up to 5.0 × 1.2 cm), upper bracts smaller, whitish-green, glabrous at base, green sparsely puberulous on both sides at apical half, connate to one another in lower 1/3–1/2, slightly reflexed at apex, all except the uppermost bract fertile. Cincinni with up to 7 flowers at the basal bracts, the number of flowers per cincinnus gradually decreasing upwards. Bracteoles one per flower, oblongoblanceolate, largest up to 15 × 5 mm (at broadest point), others gradually smaller, hyaline, translucent-white, generally glabrous, but with sparse hairs at apex, along the keel. Flowers ca 5.5–6.0 cm, well exserted from bracts. Calyx 11–12 mm, with three obscure teeth, unilaterally split for 3–4 mm from apex, white, generally glabrous, with a short sparse hairs at teeth. Floral tube ca 3.5–3.8 cm long, narrowly cylindrical, slightly widening towards the apical part, externally pure white, mostly glabrous except apical funnel-shaped part being sparsely puberulous, internally white, hairy in apical part; dorsal corolla lobe obovate, ca 12–14 mm, 4 mm at base (6–7 mm at widest point), concave, glabrous, white, apex slightly cucullate with a small mucro (ca 0.5–1 mm), glabrous; lateral corolla lobes ca 10 × 4 mm, triangular-oblong, apex rounded, slightly concave, glabrous, white. Lateral staminodes oblanceolate-spathulate, up to 16mm long, 5 mm at broadest point, pure white. Labellum ca 2.2 × 2.0 cm, orbicular, apex split ca 4 mm, pure white on sides, with rich yellow, welldefined median, the sides of the basal half of the median patched with red. Stamen 10 mm, pure white throughout; anther spurless, 7.5 × 2.0 mm, with glandular hairs on the sides of the connective; filament ca 3 mm long, ca 3 mm broad at base, ca 1.5 mm at the point of attachment to connective, glandular hairs sparsely present; anther thecae 3.5–4.0 mm, dehiscing along the entire length; anther crest present, 3–4 × ca 3 mm, glabrous. Stigma white, funnel-shaped, funnel flattened from front and back, ostiole front-top facing, ciliate. Epigynous glands absent. Ovary ovoid, 2.5-3 × 2 mm, trilocular, white, glabrous. Fruit (possibly not fully mature; described from a spirit material) obovoid, 1 × 7 mm, with persistent calyx, ca 11 seeds, seeds ovoid, 4–5 × 2 mm, mid-brown, glabrous, with laciniate arils (translucent white?).

Etymology:— We dedicate this small but beautiful species to Prof. Leonid V. Averyanov, who first brought this species to our attention. Prof. Averyanov made exemplary contributions to the knowledge of Vietnamese Orchidaceae . With his main Vietnamese collaborators, Prof. Phan Kế Lộc and Dr. Nguyễn Tiến Hiệp, he also conducted multiple expeditions during past 20 years leading to great enhancement of general floristic and phytogeographic knowledge of Vietnam and adjacent areas of eastern Indochina (e.g. Averyanov et al. 2003).

Distribution & IUCN preliminary assessment:— So far known only from several sites in Bù Gia Mập National Park, southern Vietnam. As this species has been reported so far only from less than five locations in Bù Gia Mập National Park (c. 260 km 2 surrounded by a buffer zone of increasingly more populated areas and agricultural plantations), this species should be considered for the placement in the Endangered category, EN B1ab (i, ii).

Ecology and phenology:— The species is typically found in understory of lowland, broadleaved, evergreen forest, usually near streams, at around 350–400 m elevation. Flowering occurs between April to May, fruiting around July.

Figures

FIGURE 1. Curcuma leonidii A. Habit. B. Inflorescence. C. Flower. D. Anther (front, back and side views, scale bar 5 mm). Photo: LƯu Hồng TrƯƠng.