Zingiber bambusifolium subsp. magenteum L.Bai, 2025

Zingiber bambusifolium subsp. magenteum L.Bai , subsp. nov. Ǩ唇乌姜 (zǐ chún wū jiāng) Figs. 6–7 View FIGURE 6 View FIGURE 7 .

Type:— CHINA. Guizhou Province, Qianxinan Buyei and Miao Autonomous Prefecture, Xingyi City, Xiawutun Village, limestone hills, elev. 1202 m, 104.907152°E, 25.051440°N, 20 August 2023, L. Bai & Y. Y. Zhang BLSC-321 (holotype IBSC!, isotypes GXMI!, HITBC!, IBK!, KUN!)

Diagnosis. Differs from the typical subspecies in labellum and lateral staminodes being pale yellow with pale to dark purplish red tinge (vs cream in Z. bambusifolium subsp. bambusifolium ), lamina broader (3–5 cm vs 1.8–3.5 cm). rhizome pale yellow (vs beige to peach coloured or dark purplish black) and vegetative rhizome units sometimes with a pseudo-neck 1–10 cm long (vs vegetative rhizome units without pseudo-neck).

Other specimens examined (paratypes):— CHINA. Guizhou Province: Qianxinan Buyei and Miao Autonomous Prefecture : Xingren County, Xiashan Village , C. Z. Dang 80616 ( HGAS, [barcode 048553 and another sheet without barcode]) ; Xingren County, Haizi Village , 1400–1450 m, 10 October 1998, Sino-Japan expedition 100700 ( KUN [barcodes 0336574]) & 100264 ( KUN [barcodes 0336577]) ; Xingren County, Yuzhang Village , 1470 m, 8 October 1998, S. G. Wu et al. 100878 ( KUN [barcodes 0336578]) ; Xingyi City, Jingnan Village, Heimajiao Hamlet , elev. 1500 m, Anshun Expedition 677 ( HGAS barcode 048554) ; Xingyi City, Xiawutun Village , 5 November 2023, L. Bai BLSC - 327 ( IBSC) ; ibid., elev. 1184 m, C. Y. Deng 522301140906511 LY, 6 September 2014 ( GZTM [barcodes GZTM0059899 About GZTM & GZTM0059900 About GZTM ]) ; Xingyi City, Maling River Canyon , elev. 970 m, X. Hu et al. Hu-252 ( IBSC [barcode 0804994]) ; Xingyi City, Maling River Canyon , elev. 998 m, L. Bai et al. BLSC-320 ( IBSC) . Yunnan Province: Wenshan Zhuang Autonomous Prefecture, Guangnan County, Zhulin Village , elev. 1494 m, 21 August 2024, L. Bai BLSC-24082101 ( IBSC) ; Wenshan Zhuang Autonomous Prefecture, Qiubei County, Shuanglongying County , elev. 1489 m, 22 August 2024, L. Bai BLSC-24082201 ( IBSC) .

Ecology & Phenology:— Zingiber bambusifolium subsp. magenteum grows in understories of limestone hills. Rhizomes are often covered by thick litter layers. The elevation of occurrence is between 970 m to 1500 m. Flowering commences from mid-August and probably extends to late September. Fruits start to mature from October but last till late November.

Distribution & Conservation status:— Zingiber bambusifolium subsp. magenteum is currently known from Xingren County and Xingyi City of Qianxinan Buyei and Miao Autonomous Prefecture, Guizhou Province and Wenshan Zhuang Autonomous Prefecture, Yunnan Province in southwestern China ( Fig. 5 View FIGURE 5 ). The Extent of occurrence (EOO) is about 7400 km 2. In the three spots I collected the subspecies, it forms rather large populations. The subspecies is not known to be harvested as medicine or vegetables.At present, I therefore propose to treat Z. bambusifolium subsp. magenteum as ‘Least concerned’ (LC) according to the latest IUCN Criteria (IUCN 2012, 2019).

Affinities:— Apart from the typical subspecies, Z. bambusifolium subsp. magenteum is also superficially similar to Z. tenuifolium Bai et al. (2015: 92) . Zingiber tenuifolium is so far only known from a few populations in Xinping County, Yuxi City, Yunnan Province, about 200 km west of the nearest occurrence of Z. bambusifolium subsp. magenteum (see Fig. 5 View FIGURE 5 ). It grows in sandstone and shale-derived substrates along creek in an elevation of 500– 700 m. Zingiber bambusifolium subsp. magenteum differs from Z. tenuifolium by broader lamina (3–5 cm), corolla lobes cream to yellow with red tinge, lateral staminodes connate to labellum at basal 2/3–4/5 and vegetative rhizome units sometimes much elongated (pseudo neck 1–10 cm long). In Z. tenuifolium , laminae are 1.5–3 cm wide, corolla lobes are reddish brown, lateral staminodes connate to labellum at basal 1/3–1/2, vegetative rhizome units never elongated (lacking a pseudo-neck). Although the differences seem to be subtle, unpublished phylogenetic study shows that the two entities are not especially closely related.

Etymology:— The subspecies epithet magenteus (meaning red-purple ( Stearn 1992)) refers to the purple-red labellum and lateral staminodes.

Notes: Zingiber bambusifolium subsp. magenteum seems to hybridize with Z. densissimum Tong & Xia (1987: 467) . Putative hybrid individuals (L. Bai BLSC- 24082102 & L. Bai BLSC- 24082202) are seen in the two populations of Z. bambusifolium subsp. magenteum from Wenshan Zhuang Autonomous Prefecture in Yunnan. Although Z. densissimum is not seen in the same localities, they do occur in the general area of Wenshan Zhuang Autonomous Prefecture. Zingiber tenuifolium was also suspected to hybrid with Z. densissimum (Bai et al. 2024) .