Zingiber purpureum subsp. perdurans L. Bai, 2025

Bai, Lin, Ding, Hongbo & Li, Yong Liang, 2025, Taxonomic studies on Zingiber (Zingiberaceae) in China VIII: Zingiber purpureum subsp. perdurans (Zingiberaceae: Zingiberoideae), a new subspecies from Yunnan, China, Phytotaxa 694 (3), pp. 264-270 : 265-266

Zingiber purpureum subsp. perdurans L. Bai subsp. nov. 多ƚṝà姜 (duō máo zǐ sè jiāng) ( Figs. 1–2 ).

Type: — CHINA. Yunnan Province, Lincang City, Yongde County, Daxueshan Yi, Lahu & Dai Autonomous Township , Xunfang, 24.036667°N, 99.751853°E, elev. 951 m, 16 August 2024, L. Bai BLSC-24081606 (holotype: IBSC, barcode 1029995!; isotypes: HITBC, HITBC0124409 !; IBSC, barcodes 1029996 & 029997!; KUN, barcodes 1630395 & 1630396!; SING!) .

Diagnosis -This new subspecies shares several characteristics with Z. purpureum subsp. purpureum : bright yellow rhizome (lemon-yellow when fresh, becoming slightly saffron-coloured when dry) with a camphoraceous smell, narrowly elliptic laminae, short ligules, cone-shaped inflorescences with dark red to maroon, purplish or almost brown bracts, and cream-coloured, wrinkled, and deeply incised labella. However, it differs significantly in its dense, long, erect, coarse indumentum on the whole lower lamina surface and upper lamina midveins, as well as the whole ligules and leaf sheaths, and in its broader (2.3–2.9 cm) and more prominently wrinkled labellum. Zingiber purpureum subsp. purpureum has glabrous leaves (except midvein on lower surface of laminae, and the margins of leaf sheaths and ligules are covered by long straight hairs) and a narrower labellum (1.7–2 cm wide).

Description. Rhizomatous herbs, 100–150 cm tall, forming clumps, each clump with up to 20 leafy shoots. Rhizomes compact, bright yellow externally and internally (lemon-yellow when fresh, becoming slightly saffron-coloured when dry), with a strong camphoraceous smell, rhizome units appear in ventrodorsal position in relation to its antecedent units; vegetative rhizome units oblong ovoid, curved upwards, 3–5 cm long, 2–3.5 cm in diam. at broadest point, 1.5–2.5 cm at apex, 1–1.5 cm at base, with 6–8 internodes per unit, internodes 0.4–1 cm long; flowering rhizome unit smaller, cylindrical, ca. 1 cm long and 1 cm in diam. Leafy shoots erect, with 25–30 laminae; bladeless sheaths 2–3, 5–15 cm long, greenish purple or green, densely hirsute; leaf sheaths light green to yellowish green, with marron tinge, densely hirsute. Ligules bilobed, 1–4 mm long, light green, with red tinges, with dense, erect coarse hairs, apices of lobes obtuse to acute; petioles subsessile or very short, up to 5 mm long, consist of pulvinus only, densely hirsute; laminae narrowly ovate, 30–35 × 4–5.5 cm (length:width ratio 6.5–11.5), adaxially yellowish green, glabrous except long erect hairs along the mid-vein, abaxially pale green, with dense, erect coarse hairs (ca. 2 mm long), apex attenuate, base obtuse to attenuate. Inflorescences up to 6 per clump, arising from rhizome; peduncles erect, 15–40 cm long, covered by 7–8 sheathing bracts; basal sheathing bracts triangular-ovate, upper ones narrowly oblong-ovate, green with rich marron tinge, glabrous adaxially, densely hirsute abaxially; spikes narrowly ovoid to narrowly conical, 10– 13 × 3.5–4.5 cm, consisting of 35–47 fertile bracts, each subtending a single flower; bracts broadly ovate to obovate, slightly convex and densely imbricate, dark red to maroon, purplish or almost brown, base greenish yellow, margins sometimes greenish, whole bracts turning red in fruiting, 3.5–4.5 × 2.5–3 cm, adaxially glabrous, abaxially densely hirsute, apex broadly acute; bracteoles narrowly ovate, rolling into a tube, 3.2–3.7 cm long, 1–2 cm wide, abaxially glabrous, abaxially densely hirsute. Flowers exserted from bracts, 6.5–7 cm long; calyx narrowly campanulate, 16–18 mm long, 3.5–4 mm in diam. at base, 5.5–6 mm in diam. at broadest point, cream, externally puberulous, apex with three teeth; floral tube narrowly cylindrical, slightly widening distally, 30–36 mm long, 3.5–4 mm in diam. at base and 4–4.5 mm in diam. at apex, cream, externally puberulus, internally glabrous at base, pubescent near the throat; dorsal corolla lobe triangular-ovate, 24–27 × 10–12 mm, pale yellow with semi-translucent veins, abaxially pubescent, apex acute; lateral corolla lobes narrowly triangular-ovate, 20–24 × 8–11 mm, pale yellow with semi-translucent veins, abaxially pubescent, apex acute; labellum broad obovate to orbicular, 22–25 mm long, 23–29 mm at widest point, cream, sometimes with slight pink tinge towards the base, glabrous, apex deeply incised (to 1/3–2/5 of the length), margin prominently winkled; lateral staminodes broadly ovate with obtuse apex, 10–12 × 8–10 mm, cream, winkled, glabrous, adnate to labellum at basal ca. 1/2; stamen 15–20 mm long; anthers 14–19 mm long, ca. 3.5 mm wide, connective appendages cream, glabrous; anther thecae 11–12 mm long, dehiscing along the entire length. Ovary cylindrical, 5.5–6 × 3.5–4 mm, pale yellow with dense, appressed, coarse hairs, trilocular with axile placentation; style white, glabrous; stigma slightly thicker than style, white, ostiole ciliate. Fruits unknown.

Additional specimens examined (paratypes):— CHINA. Yunnan Province, Lincang City, Yongde County, Daxueshan Yi, Lahu & Dai Autonomous Village, Shangbankong, 24. 0086389 °N, 99.74733333°E, elev. 734 m, 20 November 2007, Y.L. Li YDDXSB-192 (KUN, barcodes 1390786, 1390787, 1390789, 1390790 & 1390791).

Ecology & Phenology:— Zingiber purpureum subsp. perdurans grows in sandy soil in grassy scrubs near the semi-humid gully. The elevation of occurrence is between 730 m to 1000 m. It flowers from late July to late August. Fruits unknown.

Distribution & Provisional Conservation Status:— Zingiber purpureum subsp. perdurans is so far only known with certainty from two sites that are about 5 km apart. One of the sites is now flooded and the species is probably no longer distributed there. The other one is also apparently threatened by agricultural activities. An examination of specimens of Zingiberaceae at major Chinese herbaria (GXMG, GXMI, HITBC, IBK, IBSC, KUN, NAS and PE) as well as digital images of specimens that are provided in National Specimen Information Structure ( Institute of Botany 2024, continuously updated) did not find any specimens of the subspecies. The occurrence outside China is uncertain (see notes). Further field observation is necessary to better assess plant numbers and distribution. Currently, it is best to treat the subspecies as ‘Data Deficient’ (DD) according to the latest IUCN Criteria (Standards and Petitions Committee of the IUCN Species Survival Commission 2024).

Etymology:— The subspecific epithet is derived from the Latin perdurans (meaning ‘persistent, enduring’ ( Stearn 1992)), a reference to the fact that the species is currently surviving at the grassy gully between macadamia plantations.

Notes:— Although Zingiber purpureum subsp. purpureum is a widely used medicinal plant, there was long-time nomenclature puzzles surrounding the entity. In the past century, this entity was generally named Z. cassumunar Roxburgh (1810: 317) or Z. montanum , until Bai et al. (2019) pointed out that Z. montanum represented a different species and the earliest legitimate name for this medicinal plant was Z. purpureum . In the absence of original material, a specimen collected by J. Shepherd from the Liverpool Botanic Garden in 1824 was selected as a neotype of Z. purpureum to fix the application of the name. Synonyms relevant to Z. purpureum that appeared in literature were reviewed in Bai et al. (2019) and they all represent the typical subspecies, i.e. the leaves are generally glabrous except the margin of leaf sheaths and ligules and mid-vein of the lower surface of laminae.

Zingiber purpureum was originally described based on an introduced plant of unknown origin ( Roscoe 1807). The natural distribution of Z. purpureum subsp. purpureum remained unknown. Judging from the habit, we believe Z. purpureum subsp. perdurans was native to the sites in Lincang City, Yunnan. No usage is known according to our native field guide. A collection from Mandalay, Myanmar, J.H. Lace 5407 (E! barcodes E00389832 & E00389833), which is about 400 km southwest of the type locality, most likely also represents Z. purpureum subsp. perdurans . However, future field study is needed to confirm its identity.

As mentioned in the introduction, Zingiber purpureum subsp. perdurans is also generally similar to Z. corallinum . Zingiber corallinum was reported as occurring in Yunnan in Wu & Larsen (2000). However, all specimens from Yunnan that were identified as Z. corallinum represent misidentification of Z. kerrii (e.g. C.W. Wang 80543 (PE), C.W. Wang 80620 (PE)), Z. neotruncatum Wu et al (2000: 91) (e.g. C.W. Wang 79254 (PE)), Z. purpureum subsp. purpureum (e.g. G.D. Tao 12872 (HITBC)) and Z. xishuangbannaense Tong (1987:461) (e.g. Yunnan Tropical biological resources Survey 59-13282 (NAS)). The species is not known to occur in Yunnan. Apart from having broader laminae (3.5–7 cm) and longer ligules (3–8 mm), the reproductive part of Z. corallinum is also rather different from Z. purpureum subsp. perdurans . The spikes are generally longer (15–32 cm), while labella (1.5–2 × 0.9–1.6 cm) and lateral staminodes (0.7–1.1 × 0.2–0.5 cm) are smaller. The bracts are red in fruit for both species. However, when flowering, the bracts of Z. corallinum are green, while the bracts of both subspecies of Z. purpureum are dark red to maroon, purplish or almost brown. The rhizomes of both species have a strong camphoraceous smell, but those of Z. corallinum are cream externally, cream to pale orange-pink to peach coloured internally ( Bai & Xia 2024), while those of both subspecies of Z. purpureum are yellow externally and internally (lemon-yellow when fresh, becoming slightly saffron-coloured when dry).

Figures

FIGURE 1. Zingiber purpureum subsp. perdurans. A. Plant habit. B. Ligules and leaf sheaths. C. Leafy branch, abaxial view. D. Rhizome. Based on the type collection, L. Bai BLSC-24081606, collected from Yongde County, Yunnan Province. Photos: L. Bai.

FIGURE 2. Zingiber purpureum subsp. perdurans. A–B. Inflorescences. C. Flowers (front view and side view). D. Flowers (apical view). E. Flower. F. Flower dissection: bract (b), bracteole (bl), calyx (ca), dorsal corolla lobe (dc), two lateral corolla lobes (lc), upper surface (l+ls (adaxial)) and lower surface (l+ls (abaxial)) of labellum and lateral staminodes, floral tube and anther (ft+an), ovary with two epigynous glands (o). Based on the type collection, L. Bai BLSC-24081606, collected from Yongde County, Yunnan Province. Photos: L. Bai.