Persicaria zhenaiguoi Bo Li, 2025

Wei, Yi-Ming, Zhu, Zhen-Hua, Lei, Shu-Qing & Li, Bo, 2025, Persicaria zhenaiguoi (Polygonaceae, Persicarieae), an overlooked new species from Dabie Mountains, central China, PhytoKeys 253, pp. 11-19 : 11-19

Persicaria zhenaiguoi Bo Li sp. nov.

Figs 1 , 2 A 1 – A 5

Diagnosis.

Morphologically, P. zhenaiguoi is superficially most similar to P. orientalis and P. viscosa in the indumentum characteristic, but can be clearly distinguished from the latter two taxa by its nearly sessile leaves, which are lanceolate in shape with broadly cuneate to rounded bases, membranous ocrea with a small circle of green leaf-like wing, sparse and interrupted inflorescences, glabrous peduncles, greenish tepals, and ovoid achenes with grooved surfaces (Fig. 2 , Table 1 ).

Type.

China • Hubei Province, Huanggang City, Yingshan County, Tiantangzhai Town, Dabie Mountains, in the grassland at the summit of Tiantangzhai Peak , 31°06'21.44"N, 115°46'22.60"E, alt. 1712 m, 10 July 2023, X. X. Zhu et al. ZXX 23818 (holotype: HITBC 0122106 , isotype: IBSC 0923376 ) .

Description.

Herbs annual. Stems erect, slender, angulate, 20–50 cm tall, densely spreading villous. Petiole connate with lower parts of ocrea, nearly absent; Leaf blade lanceolate, 2.8–5.3 × 0.6–1.1 cm wide, apex acuminate, base broadly cuneate to rounded, margin densely ciliate, both surfaces densely villous, midvein slightly hollow on the adaxial surface and rise on the abaxial surface, lateral veins 8–10 pairs. Ocrea tubular, membranous, 0.6–1.1 mm long, densely villous, margin truncate with long ciliate and a small circle of green leaf-like wing. Inflorescence terminal or axillary, spicate, 2.8–5.1 cm long, slender, interrupted below, usually several spikes aggregated and panicle-like; peduncle glabrous. Bracts green, funnel-shaped, 2.8–4.6 mm long, sparsely villous, margin long ciliate, each 2–4 flowered. Pedicels slightly longer than bracts. Perianth greenish, 5 - parted; tepals elliptic, 2.3–3.4 mm. Stamens 8, included. Styles 3, connate to below middle; stigma capitate. Achenes included in persistent perianth, 1.6–2.1 × 0.8–1.2 mm, brown, shiny, long ovoid, trigonous, surfaces grooved.

Phenology.

Flowering and fruiting was observed synchronously from July to October.

Etymology.

The specific epithet “ zhenaiguoi ” is dedicated to Professor Ai-Guo Zhen, in recognition of his significant contributions to the study of the local flora and biodiversity in Yingshan County.

Vernacular name.

The Chinese name of the new species is “ 甄氏蓼 ”, and the pronunciation of the Chinese Pinyin is zhēn shì liǎo.

Distribution and habitat.

Persicaria zhenaiguoi can be found above an altitude of 1.600 m, in the moist grassland at the summit of Tiantangzhai Peak, one of the main peaks of the Dabie Mountains, which are located on the border between Hubei and Anhui provinces (Fig. 3 ). This plant is typically found growing alongside species of Dryopteris Adanson and Carex L.

Preliminary conservation status.

As currently known, this species has only been discovered from its type locality in the Tiantangzhai Peak of the Dabie Mountains, where it is distributed in a small area within the mountaintop region. Moreover, its habitat is increasingly threatened by the growing development of local tourism (author’s personal observation). Therefore, it should be categorised as critically endangered under criteria B and D following IUCN Red List Categories ( IUCN 2012).

Taxonomic notes.

Morphologically, the ocrea of all species within P. sect. Persicaria is tubular and membranous, with a truncate, mostly ciliate apex ( Meisner 1856; Gross 1913; Steward 1930; Haraldson 1978; Tutin et al. 1991; Li et al. 2003; Freeman 2005). Before this, P. orientalis was the only species in this section known to typically have a circle of green, leaf-like wing at the apex of the ocrea (Fig. 2 B 3 ). P. zhenaiguoi is the second species to exhibit a similar structure, caused by the enlargement of the longitudinal veins at the apex of the ocrea (Fig. 2 A 3 ), although not as prominent as observed in P. orientalis . They also share the similar indumentum that are long spreading white hairs densely covering on stems, leaves as well as ocreae, but are clearly different from each other in plant size (Fig. 2 A 1, B 1 ), leaf shape and size (Fig. 2 A 2, B 2 ), inflorescence structure (Fig. 2 A 4, B 4 ), as well as the fruit shape (Fig. 2 A 5, B 5 ). Persicaria viscosa is another species having the same indumentum and much more similar to P. zhenaiguoi in gross morphology, but it differs from the latter in several aspects: its leaf bases are long decurrent along petioles (Fig. 2 C 2 ), the peduncles cover dense hirsute and glandular hairs (Fig. 2 C 1, C 4 ), and the inflorescences are dense and pinkish (Fig. 2 C 4 ). Detailed morphological comparisons among these three taxa are listed in the Table 1 .

It is worthy to mention that the habitat and distribution of P. zhenaiguoi are somewhat unusual, at least when comparing with other species in sect. Persicaria found in central and southern China. Based on our years of observation, species from sect. Cephalophilon and sect. Echinocaulon , such as P. nepalensis (Meisn.) H. Gross , P. runcinata var. sinensis (Hemsl.) Bo Li , and P. thunbergii (Siebold & Zucc.) H. Gross , are easily found in habitats like the summit of Tiantangzhai Peak (Fig. 1 A ). However, species from sect. Persicaria are rarely occurring at such high altitudes. At the same time, there has been a lack of comprehensive and in-depth surveys of the plant flora in the Dabie Mountains, especially in the mountaintop areas. This may explain why P. zhenaiguoi has likely been overlooked and not collected in the Dabie Mountains until now.

Additional specimens examined.

Persicaria orientalis : China • Anhui Province, Shucheng County, Xiaotian Town , 1 October 1951, East China Workstation 4162 ( PE 00497378 !) ; • Chongqing Municipality, Nanchuan County, Sanquan Village , alt. 640 m, 14 October 1985, Z. Y. Liu 7429 ( IMC 0038461 !) ; • Guangdong Province, Yangjiang City, Jiangcheng District, Hailing Town , 21°37'36.42"N, 111°58'8.87"E, alt. 27 m, 6 April 2021, G. W. Tang et al. TangGW 1343 ( KUN 1556765 !) ; • Guizhou Province, Congjiang County, Doli Town, Panli Village , 25°35'14.35"N, 108°59'11.11"E, alt. 672 m, 21 September 2019, K. T. Liu 522633190921914 LY ( GZTM 0096269 !) ; • Hainan Province, Haikou City, Longhua District, Xue Village , 19°57'39.19"N, 110°20'57.89"E, alt. 15 m, 2 May 2018, Y. T. Hou et al. 20180426580-1 ( QFNU 0048156 !) ; • Hebei Province, Longhua County, Bugugou Town , alt. 993 m, 20 August 2013, Group Six Z 0272 ( HBNU 20001289 !) ; • Heilongjiang Province, Qiqihar City , Longjiang County, 47°19'23"N, 123°11'41"E, alt. 131 m, 25 August 2019, L. Y. Lin 2019082501 ( JMSMC 0000049 !) ; • Henan Province, Xinxiang City, Huilong Village , 35°35'02"N, 113°35'57"E, alt. 369 m, 12 July 2018, J. R. Li 368 ( HENU 1900368 !) ; • Hunan Province, Nanyue District, Hengshan Nature Reserve , alt. 300 m, 1 September 2002, Z. H. Hu 533 ( PE 00497445 !) ; • Jiangsu Province, Suqian City, Siyang County, Longji Town , 33°20'40.36"N, 118°38'19.97"E, alt. 18 m, 3 August 2019, Y. T. Hou et al. 20190803230-1 ( QFNU 0052420 !) ; • Jiangxi Province, Fengchen City, Xiushi Town , grassland, 27°51'38.81"N, 115°53'15.04"E, alt. 423 m, 3 October 2019, L. Cao 360981191003305 LY ( JXCM 0010118 !) ; • Shandong Province, Zouping City, Xiyu Village , 36°47'17"N, 117°40'49"E, alt. 342 m, 4 August 2018, J. L. Lan 201808037-1 ( QFNU 0047293 !) ; • Shanxi Province, Wanrong County, Jiachun Town , 32°21'0"N, 110°37'0"E, alt. 566 m, 28 July 2020, Y. J. Feng 201941325966 ( QFNU 0059553 !) ; • Zhejiang Province, Jinyun County, Huzhen Town, Xiaxiang Village , 28°47'23"N, 120°12'58"E, alt. 194 m, 2 July 2013, H. Y. Shou & Z. H. Wang SHY 00909 ( CSH 0012891 !) .

Persicaria viscosa : China • Chongqing Municipality, Zhong County, Baishi Town , Huangjia Village , 30°20'17.78"N, 107°56'28.29"E, alt. 624 m, 30 May 2013, Zhong County Team 500233-130530 - 519 - 03 ( IMC 0045792 !) ; • Guangxi Province, Liuzhou City, Liujiang County, Jinde Town, Siliang Village , 24°15'44.59"N, 109°20'25.69"E, alt. 114 m, 14 August 2018, Liujiang Team 450221180814022 LY ( IBK 00425346 !) ; • Heilongjiang Province, Jiamusi City, Huachuan County, Shenjiadian Village , 46°34'39.68"N, 130°37'48.81"E, alt. 189 m, 8 September 2018, C. Wang & Y. G. Peng WangCh 532 ( KUN 1554918 !) ; • Henan Province, Xinyang City, Shihe District , 32°6'52.15"N, 114°0'33.63"E, alt. 87 m, 8 June 2020, X. X. Zhu et al. ZXX 20942 ( HIB 0187735 !) ; • Hubei Province, Hongan County, Xinhua Town, Zhangshan Village , alt. 80 m, 14 June 2019, C. M. Tan et al. 19061418 ( JJF 00044259 !) ; • Hunan Province, Shaoyang City , Dongkou County, alt. 350 m, 12 August 2004, L. D. Duan 5337 ( PE 00640285 !) ; • Jiangxi Province, Jiujiang County, alt. 250 m, 17 September 2005, A. M. Dong 930 ( SZG 00002585 !) ; • Jilin Province, Baishan City, Badaojiang District , 41°34'12.01"N, 126°34'33.24"E, alt. 311 m, 22 August 2019, C. Q. Cao CaoChQ 495 ( KUN 1487264 !) ; • Yunnan Province, Baoshan City, Tengchong County, Qushi Town , 25°23'58"N, 98°50'54"E, 1820 m, 3 October 2009, Y. F. Chen et al. 09209-3 ( QFNU 0056773 !) ; • Shandong Province, Yantai City, Rizhao Village , 36°48'5"N, 121°18'55"E, alt. 18 m, 28 September 2015, X. W. Xin Lilan 859 ( KUN 1438272 !) .

Figures

Figure 1. Habitat and morphology of Persicaria zhenaiguoi Bo Li, sp. nov. A habitat B habit C stem D adaxial view of leaf blade E abaxial view of leaf blade F ocrea (the red arrow shows the green leaf-like wing) G inflorescence H achene I roots (photographed by Dr. Xin-Xin Zhu).

Figure 2. Morphological comparisons among P. zhenaiguoi (A 1 – A 5), P. orientalis (B 1 – B 5), and P. viscosa (C 1 – C 5) A 1, B 1, C 1 habit A 2, B 2, C 2 leaves A 3, B 3, C 3 ocrea A 4, B 4, C 4 inflorescences A 5, B 5, C 5 achenes.

Figure 3. Distribution of P. zhenaiguoi (marked by the red circle).