Zingiber hainanense Y.S. Ye, L. Bai & N.H. Xia, 2015

Ye, Yu-Shi, Bai, Lin & Xia, Nian-He, 2015, Zingiber hainanense (Zingiberaceae), a new species from Hainan, China, Phytotaxa 217 (1), pp. 73-79 : 75-77

Zingiber hainanense Y.S. Ye, L. Bai & N.H. Xia , sp. nov. ( Figures 1–3 )

Type: — CHINA: Hainan Province: Wuzhishan City, Maoyang Zhen, Maolu Cun, Yinggeling Nature Reserve, by the stream sides on the valleys, altitude around 500–800 m, 26 September 2005, Yushi Ye 5626 (holotype IBSC!).

Diagnosis: Similar to Zingiber guangxiense in narrowly ovate, loosely arranged bracts, narrow labellum and lateral staminodes, and bifid apex of labellum, but differs by labellum and staminodes being purple red (versus yellowish white throughout). It is also similar to Z. kawagoii in narrowly ovate, loosely arranged bracts, purplish labellum and lateral staminodes, bilobed ligules, but differs from it by labellum and lateral staminodes being linear or narrowly ovate (versus obovate-oblong).

Perennial rhizomatous herb ca. 1 m tall. Rhizomes fleshy, branched, 8–20 mm in diameter, light brown externally, old rhizomes internally white to pale yellow with light purple outer layer, young rhizomes deep purple; root tubers ovate, internally ivory. Leafy shoots with up to 12 leaves when flowering; leaf sheaths longitudinally striate, white pubescent, lower sheaths purple red, upper ones green; ligule 3–4 mm long, bilobed, apices triangular, membraneous, scarious on the margin, densely pubescent; petiole 2–3 mm, consisting of pulvinus only, pubescent; lamina elliptic to narrowly-elliptic, 12–25 × 2.8–5 cm, adaxially green to dark green, sparsely pubescent along sides of midvein, abaxially pale green, densely pubescent, base obtuse to rounded, apex acuminate. Inflorescences 2–3, radical; peduncles 0.5–2 cm long, embedded underground, scales oblong; spikes obovoid, 3–5 × 2–3 cm, few-flowered with loosely arranged bracts (ca. 8); sterile bracts 2–4 × 1.6–2 cm, narrowly ovate, greenish with dense purplish-red tinge, apex obtuse or retuse, fertile bracts each subtending one flower, narrowly ovate, yellowish green with reddish tinge, 3–4 × 0.6–1 cm, apex acute; bracteoles narrowly ovate, apex acute, ca. 25 × 7 mm, semi-translucent, yellowish green at base, with green-purple tinge at apex. Flowers 6–7 cm long, much exserted from the bracts; calyx tubular, membranaceous, 13 mm long, unilaterally split to 5 mm, apex tri-dentate, bearded on each denticles, sparsely pubescent on the base outside, glabrous inside, pale greenish white, with black-purple tinge at apex; floral tube white, 25–40 mm long; dorsal lobe narrowly ovate, ca. 30 × 7–8 mm, pink-red, concave, sparsely pubescent outside, glabrous inside, apex mucronate; lateral lobes narrowly ovate, ca. 25 × 3–4 mm, pink-red, deflexed, sparsely pubescent outside, glabrous inside; labellum linear to narrowly ovate, 23–33 × 2–6 mm, purple with cream white base, apex bifid (rarely entire); lateral staminodes linear to narrowly ovate, 10–18 × 2–5 mm, purple, apex acute. Stamen ca. 30 mm long; filament ca. 3 mm long, 2.5mm wide, anther ca. 12 mm long, connective tissue yellow, anther thecae 12 mm long, dehiscing throughout entire length, pollen light yellow, anther crest beak shaped, 12–15 mm long, purple red, apex bifid, rarely entire. Style filiform, white, glabrous; stigma funnel form, white or slightly pale purple, ostiole ciliate. Ovary cylindrical, pale yellowish green, trilocular, ca. 7 × 3 mm, densely pubescent; Epigynous glands two, pale yellow, ca. 4mm long, 0.3mm in diameter, apex blunt. Fruits ovoid trigonous capsule, 35 × 15–20 mm, greenish-cream with pink-red tinge externally, glossy red internally; seeds slightly obovoid, 4–6 × 2.5–3 mm, dark brown to black, striate, aril white, sac-like, with irregularly edged apex, covering most of the seed.

— A. Habit.— B. Flowers with bifid labellum.— C. Flower with bifid anther crest.—D. Crossection of the old rhizome.— E. Crossection of young rhizome near leafy shoot.— F. Inflorescence.— G. Infructescence.— H. Ligule. Photo: Yushi Ye

Pollen morphology: —The pollen grains of Zingiber hainanense are sub-globose, inaperturate and with spiro-striate sculpturing, 72.98 ± 7.48 × 50.61 ± 4.81 um, P / E ratio 1.33 on average (1.02–1.70) ( Figure 3 )

Cytology: —The chromosome number of Zingiber hainanense is 2n = 22.

Etymology: —The specific epithet denotes that this species is endemic to Hainan.

Distribution and preliminary IUCN assessment: — Zingiber hainanense is endemic to Hainan, China. Up to now, it is known only from 4 localities apart from type locality. The extent of occurrence estimated to be 2800 km 2 and its habitat area is declining due to deforestation. Therefore, we propose to treat this species under ‘Endangered’ (EN) category (B 1 ab (iii)) according to the IUCN (2008) guidelines.

Ecology and phenology: —The species is typically found in lowland, on sand as well as soil, shade and moist places in ravines and in forests understory. Phenology of Z. haina nense is not yet well understood. The original collection, made in end of September, was in the end of flowering. In cultivation at South China Botanic Garden it flowers around September, fruiting continues until March and the plants enter dormancy around April in the next year and sprout in June.

— A. Equatorial view.—B. Polar view.

Additional material examined (paratypes):— CHINA. Hainan Province: Baoting Xian (Today’s Qiongzhong Xian), Diaoluoshan Xiang , North of Xin’an Cun , altitude 1030 m, 18 December 1954, Diaoluoshan Team 3124 ( IBSC, CDBI) ; Baoting county (Today’s Qiongzhong Xian), Diaoluoshan township , Xin’an Cun , altitude 910 m, 21 December 1954, Diaoluoshan Team 3249 ( IBSC) ; Gan’en Xian, north of Chunjiuling ( Today’s Ledong Xian , Jianfeng Zhen , Jianfeng Mountain ), 16 October 1933, H. Y. Liang 63262 ( IBSC), same location, 19 October 1933, H. Y. Liang 63504 ( IBSC) ; Qiongzhong Xian, Chengpo Qu, Changtian Cun ( Todays Qiongzhong Xian , Diaoluoshan Xiang , Changtian Cun) L. Tang 3520 ( IBSC) .

Figures

FIGURE 1. Line drawing of Zingiber hainanense Y. S. Ye, L. Bai & N. H. Xia

FIGURE 2. Color plate of Zingiber hainanense Y. S. Ye, L. Bai & N. H. Xia.

FIGURE 3. Pollen morphology of Zingiber hainanense Y. S. Ye, L. Bai & N. H. Xia