Zingiber calcicola Y.H.Tan & H.B.Ding, 2021

Ding, Hong-Bo, Quan, Dong-Li, Zeng, Xiao-Dong, Li, Jian-Wu & Tan, Yun-Hong, 2021, Zingiber calcicola (Zingiberaceae), a new species from a limestone area in south Yunnan, China, Phytotaxa 525 (1), pp. 65-69 : 65-68

Zingiber calcicola Y.H.Tan & H.B.Ding , sp. nov. ( Figs. 1–2 )

Diagnosis: — Zingiber calcicola is similar to Z. nitens Newman (2015: 124) in having terminal inflorescence and similar labellum, but differs by its prominently plicate lamina, oblong (vs. triangular) and longer lateral staminodes (1.3–1.6 cm long vs. 0.2–0.6 cm long), elliptic lamina with the size of 13–19 × 4–6.5 cm (vs. narrowly elliptic lamina with the size of 18–25 × 2–3 cm) and dwarf habit (40–55 cm tall vs. 65–100 cm tall).

Type: — CHINA. Yunnan Province: Mengla County, Huiwa village , 21°52′26″ N, 101°27′05″ E, elevation 805 m, 4 September 2020, H.B. Ding & X.D. Zeng T0566 (holotype: HITBC0057379 !, isotype: HITBC0057382 !) .

Perennial rhizomatous herbs, 40–55 cm tall, forming a loose clump, with 2–11 leafy shoots. Rhizomes to 3 cm in diam., horizontally elongated and creeping, yellowish brown (fresh rhizomes) to fuscous (drying rhizomes). Leafy shoots slender, with 6–11 leaves, basal ca. 1/3 part of pseudostem leafless; bladeless sheaths 1–3, reddish green, glabrous; leaf sheaths green, pubescent along the margin. Ligules 3–5 mm long, pubescent along the margin, apex truncate or emarginate; petiole 3–15 mm long, glabrous; lamina elliptic, 13–19 × 4–6.5 cm, apex acuminate to caudate, base obtuse, adaxially dark green and glabrous, abaxially pale green and glabrous, prominently plicate. Inflorescence terminal on leafy shoots, in upright position, peduncle sessile, spike cylindrical to fusiform, 5–8 cm long, ca. 1 cm broad, consisting of 4–8 bracts; bracts green, 2.5–3.8 × 1.3–2.0 cm, elliptic, glabrous, apex rounded, enclosing 2 flowers at the basal 3 bracts, 1 flower at the other upper bracts (occasionally only 1 flower in all bracts); bracteoles narrowly lanceolate, 1–1.7 cm long, involute, 0.4–0.6 cm wide when flattened, translucent green to white, glabrous, apex acute to obtuse. Flowers 6–6.5 cm long, much exserted beyond the bracts; calyx tubular, 1.8–2.2 cm long, ca. 3 mm in diam. at base, slightly swollen in the middle, ca. 4 mm in diam., membranaceous, semi-translucent cream-white, glabrous, with unilateral incision to 1 mm deep, with 3 teeth at apex; floral tube slender, 3.2–3.5 cm long, shallowly curved, widening gradually towards apex, cream-white and glabrous at base, brownish yellow and glabrous towards the apical part; dorsal corolla lobe lanceolate, 2.3–2.5 × 0.5–0.8 cm, yellow with semi-translucent veins, glabrous, apex attenuate; lateral corolla lobes narrowly oblong, 2.0–2.2 × 0.3–0.4 cm, yellow with semi-translucent veins, glabrous, apex attenuate; labellum oblong, 1.9–2.3 × 0.8–1.0 cm, adaxially dark maroon with small yellow dots and yellow patch in throat, with yellow stripes from base to center; abaxially yellow; glabrous, margins slightly deflexed, apex emarginate for 2 mm; lateral staminodes oblong, 1.3–1.6 × 0.2–0.3 cm, almost free from labellum, adaxially dark maroon with small yellow dots, abaxially yellow, glabrous, apex obtuse. Stamen 2.2–2.5 cm long with anther crest stretched, filament ca. 2 mm long, yellow, anther ca. 1.2 cm long (excluding anther crest) by ca. 3 mm broad, connective tissue yellow, glabrous; anther thecae ca. 1.2 cm long, dehiscing throughout entire length, pollen yellow; anther crest beak-shaped, 9–11 mm long when stretches, dark maroon with small yellow dots. Style filiform, creamwhite at base, pale yellow and thicken towards apex, glabrous; stigma extending to the tip of anther crest, funnelshaped, pale yellow, ostiole ciliate. Ovary cylindrical, slightly swollen in middle, trilocular, 3–4 × 3–4 mm, yellowish green, glabrous; epigynous glands two, linear, 4–6 mm long, pale yellow. Fruit ovoid to obovoid, 1.4–1.6 × 1–1.2 cm, with persistent calyx, pericarp semi-translucent, yellowish cream and red inside. Seeds ellipsoid, 4–5 × 3–4 mm, black, enveloped by the aril. Aril white, deep denticulate at apex, enveloping 1/3 of the length of the seeds.

Phenology: —Flowering from August to September, fruiting from September to October.

Distribution and habitat: — Zingiber calcicola is currently known only from its type locality, Mengla County, Yunnan, China. It grows on humus among rocks in tropical seasonal rain forest on limestone hills.

Etymology: —The specific epithet ‘ calcicola ’, refers to the habitat in which the species occurs.

Conservation status: —So far, Zingiber calcicola is currently known only from the type locality in south Yunnan. Although the habitat is under protected in mini nature reserve, but only one population with less than 500 mature individuals has been found, and the extent of occurrence (EOO) is less than 40 km 2, so we propose to classify it as ‘Critically Endangered’ (CR B1ab(iii,v)) ( IUCN Standards and Petitions Committee 2019).

Specimens examined (paratypes):— CHINA. Yunnan Province: Mengla County, Huiwa village , 21°52′26″ N, 101°27′08″ E, elevation 774 m, 4 September 2020, H.B. Ding & X.D. Zeng T0565 ( HITBC); ibid., 21°52′31″ N, 101°27′00″ E, elevation 717 m, 4 September 2020, H.B. Ding & X.D. Zeng T0567 ( HITBC); ibid., 21°52′27″ N, 101°27′07″ E, elevation 787 m, 6 September 2020, H.B. Ding & X.D. Zeng T0568 ( HITBC, PE, KUN); ibid., 21°52′32.39″ N, 101°27′31.40″ E, elevation 856 m, 16 August 2021, H.B. Ding, B. Yang & X.D. Zeng T0951 ( HITBC); ibid., 21°52′37.24″ N, 101°27′42.21″ E, elevation 717 m, 16 August 2021, H.B. Ding, B. Yang & X.D. Zeng T0952 ( HITBC).

Notes: Zingiber calcicola belongs to sect. Dymczewiczia due to the terminal inflorescence on the leafy shoot. It is also similar to Z. plicatum Škorničk. & Q.B.Nguy ễn in Leong-Škorničková et al. (2015: 211) and Z. sirindhorniae Triboun & Keeratikiet (2016: 2) in having terminal inflorescence and the limestone habitat, but it differs from the first in its smaller terminal inflorescence (5–8 × ca. 1 cm vs. 12–18 × 1.5–2.0 cm), yellow corolla lobes (vs. cream-white to pale yellow) and dark maroon labellum dotted with small yellow dots (vs. peach-purple to purple, with cream white or pale yellow lines). It differs from the second by its prominently plicate lamina (vs. non-plicate), truncate or emarginate ligule (vs. bilobed) and yellow corolla lobes (vs. white).

Figures

FIGURE 1. Zingiber calcicola Y.H.Tan & H.B.Ding, sp. nov.A. Habit; B. Detail of abaxial surface of lamina; C. Habit with inflorescence; D. Rhizomes; E. Ligule; F. Inflorescence (side view); G. Flower (top view); H. Flower (bottom view); I. Leaves, adaxial (leaf) and abaxial (right) view; J. Flower with bract; K. Fruit with bract; L. Infructescence; M. Bracteole; N. Calyx; O. Dorsal corolla lobe; P. Lateral corolla lobes; Q. Floral tube with labellum and lateral staminodes; R. Stamen; S. Style and stigma; T. Ovary; U. Epigynous glands; V. Cross section of fruit; W. Seeds with aril; X. Seed with aril removed. (Photographed by H.B.Ding).

FIGURE 2. The limestone habitat of Zingiber calcicola Y.H.Tan & H.B.Ding. (Photographed by Kuo Wang)