Curcuma tongii Y. H. Tan & L. X. Zhang, 2019
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publication ID |
https://doi.org/ 10.11646/phytotaxa.395.3.9 |
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persistent identifier |
https://treatment.plazi.org/id/03CB1439-7977-FFAF-FF64-FF50FA9ECFC5 |
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treatment provided by |
Felipe |
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scientific name |
Curcuma tongii Y. H. Tan & L. X. Zhang |
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sp. nov. |
Curcuma tongii Y. H. Tan & L. X. Zhang View in CoL , sp. nov. ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ).
C. tongii is similar to C. singularis with its spike composed of a few bracts, the white flowers are well-exserted from the bracts and the L-shaped anthers, but C. tongii differs by its labellum with two bright yellow swollen bars running along the median and two 6–7 mm long, deep purple red or dark red bands placed next to the yellow bands, and lateral staminodes pure cream white, fertile bracts cream white at base with increasing red tinge towards apex and margins.
Type:— CHINA. Yunnan: Menghai, Bulang mountain conifer-broadleaf forests or evergreen broad leaved forests, alt. 948 m ,, 21°38’09.84” N, 100°18’01.68” E, 24 May 2013, Yun-Hong Tan 7168 (holotype HITBC!, isotype IMDY!).
Small rhizomatous herb to 0.5 m tall. Rhizome ovoid, c. 3–5 × 2–3 cm, unbranched, light brown externally, cream white internally, slightly aromatic with bitter almond-like scent, bitter to taste; root tubers elliptic, 2–6 cm long, light brown externally, cream white internally, developing at distance from the rhizome. Leafy shoot with 2–4 leaves, usually developing after flowering; pseudostem to 15–20(–25) cm long, green, composed of sheathing bracts and leaf sheaths; sheathing bracts 1–3 × 5–20 cm long, densely white pubescent, margin ciliate, tinged with deep purple red when young, fast drying out and decaying; leaf sheaths green, glabrous; ligule up to 4–5 mm long, bilobed, membraneous, greenish white to pale red, semi-translucent, pubescent, hair white, margin ciliate; petiole 8–13 cm long, canaliculate, green, glabrous; lamina slightly unequal, elliptic, 20–26 × 8.5–10 cm, adaxially bright green, sparsely puberulent, along the secondary raised veins, glabrescent, abaxially lighter green, glabrous, margin puberulent; midrib green, adaxially glabrous, abaxially sparsely puberulent, glabrescent; base unequal, cuneate to attenuate; apex attenuate to acuminate, puberulent. Inflorescence lateral 10–15 cm long; peduncle 4–6 cm long, 1–1.5 cm diam., cream-white to pinkish, with up to 6 sheathing bracts, membrane, 1.5–7.5 × 1.0– 1.5 cm, ovate, oblong to oblong-lanceolate, apex obtuse, margin ciliate; spike 4–11 cm long, c. 4–5 cm diam. in the middle, wider apically, coma bracts absent; fertile bracts 7–12 (–15) per inflorescence, bracts broadly ovate to ovate, 4.5–5.0 × 3.0– 3.5 cm, connate in basal 1/3–1/4, cream white at base with increasing red tinge towards apex and margins, glabrous on both sides, with hyaline margins and acute apices; supporting cincinni with 3–4 flowers at the base of the inflorescence, with 1–2 flowers at the top; bracteoles absent. Flowers 5.5–6.0 cm long, exserted from bracts; calyx 16–18 mm long, 3-toothed, with unilateral incision ca 7 mm long, semi-translucent white, sparsely puberulous; floral tube 3.5–4.0 cm long, cream white, externally glabrous, internally densely puberulous at base, glandular hairy towards the throat; dorsal corolla lobe 22–24 × 6–7 mm, triangular ovate, concave, with sides rolled inwards, semi-translucent cream white with pink tinge, glabrous, mucronate at apex with mucro 1–1.5 mm long, puberulous; lateral corolla lobes 20–22 × 5–6 mm, triangular-ovate, with apical sides rolled slightly inwards, concave, semi-translucent cream white with pink tinge, glabrous, apex sometimes with a few short hairs; labellum 20–22 × 12–13 mm, obovoid, cream white, sometimes pale pinkish basally, with two bright yellow swollen bars running along the median and two 6–7 mm long, deep purple red or dark red bands placed next to the yellow bands; apex bi-lobed with incision 8–9 mm long; lateral staminodes c. 22–23 × 12–13 mm, irregularly obovate, cream white, glabrous. Stamen 14–16 mm long; filament 8–10 × 4–6 mm, cream white, densely covered with short, glandular hairs; anther c. 6–6.5 mm long, spurred; connective cream white, densely covered with short glandular hairs; anther spurs c. 4–5 × 2–2.5 mm, narrowly acute, pointing outwards (making the anther appear as L-shaped); anther crest 1.2–1.5 mm long, thick, bi-lobed; anther thecae 5.0–5.5 × 0.8–1.0 mm, narrowly obovate, dehiscing along their entire length; pollen white, sticky. Epigynous glands two, c. 5–6 mm long, 0.4–0.5 mm in diam., cream-white, apex slightly bi-lobed; style white, glabrous, basally placed in a dorsal groove of the floral tube; stigma 1.0– 1.2 mm long, 1 mm wide, capitate, cream white, with ostiole ciliate, facing forward. Ovary c. 2.5–3 mm long, tri-locular, cream white, densely pilose. Fruits not seen.
Distribution, habitat and ecology:— Curcuma tongii is known from southern Yunnan. It grows in the understory of mixed conifer-broadleaved forest, evergreen broadleaved forest, grassland and tea plantations, at an elevation of ca. 800–1300 m.
Phenology:— Flowering starts by the middle of May and continues throughout June to middle of July, fruiting might occurs in June and likely continues until July. Leafy shoot usually develops after flowering and the plants enter dormancy from November.
Etymology:— The specific epithet ‘ tongii ’, honours Professor Shao-Quan Tong (Tong ShaoQuan), who has made the greatest contribution to the taxonomy of Zingiberaceae in Yunnan.
Relationships:— Curcuma tongii is morphologically similar to C. singularis and other white-flowered species, and also similar to C. flaviflora and other yellow-flowered species form subgen . Ecomatae with its spike composed of a few bracts, the flowers are well-exserted from the bracts and the L-shaped anthers, but C. tongii differs by its pure white flowers, labellum with two bright yellow swollen bars running along the median and two 6–7 mm long, deep purple red or dark red bands placed next to the yellow bands, and lateral staminodes pure cream white, corolla tube externally glabrous, internally densely puberulous at base, glandular hairy towards the throat. A comparative analysis of diagnostic characters of the new species and its allied species is listed in Table 1.
Additional specimens examined (paratypes):— CHINA. Yunnan: Menghai, Bulang mountain, 24 May 2012, Menghai Expeditions 5328220387 ( HITBC, IMDY) ; Pu’er, Simao, Yunxian , 22 May 2018, Ji-Dong Ya 18 CS16773 ( KUN) ; Pu’er, Jinggu, Minle , 6 July 2018, Yun-Hong Tan T0158 ( HITBC) .
Conservation assessment: It is known from south Yunnan, China, eg. Menghai, Jiangcheng, Simao, Jinggu, with only five locations ( Fig 3 View FIGURE 3 ) and a few hundred mature individuals known. The AOO is 20 km 2 based on the current data. It is found in the secondary pine-broadleaf forest, grass land, coffee plantations and tea plantations. Most of the locations remain out of protected areas. The population is decreasing due to forests fragmentation and habitat degradation, so we suggest the species is therefore assessed as ‘Endangered’, (EN B2ab(i, ii, iii, iv) IUCN 2012).
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