Hedyotis austroguangxiensis M. D. Yuan & R. J. Wang, 2025

2. Hedyotis austroguangxiensis M. D. Yuan & R. J. Wang sp. nov.

Figs 4 View Figure 4 , 5 View Figure 5

Type.

CHINA • Guangxi: Chongzuo City, Ningming County, Tongmian Town , roadside, 21.711643, 107.521562, ca. 830 m a. s. l., flowering, long-styled flower, 24 April 2021, Ming-Deng Yuan & Yi-Da Xu YS 430 ( holotype: IBSC [0868775]); isotype: IBSC [0868776] GoogleMaps ).

Diagnosis.

Hedyotis austroguangxiensis is similar to H. taishanensis G. T. Wang ( Wang et al. 2018) and H. shenzhenensis Tao Chen (2007) in having shortened internodes at the base and terminal, compound-cymose inflorescences. But it can be differed from H. taishanensis by its terete stem and inflorescence rachis, obovate to ovate or oblong leaves, 3–6 secondary veins on each side, and longer corolla tubes; it differs from H. shenzhenensis by its terete stems and inflorescence axes, smaller leaves, and longer corolla tubes (Table 3 View Table 3 ).

Description.

Perennial herbs, erect, 20–50 cm tall. Stem terete, glabrous, internodes 0.5–5.0 cm long at the base and 5.0–13.0 cm long toward top. Leaves opposite, sessile, blade 2.5–15.0 × 1.5–7.0 cm, ovate to oblong, apex acuminate or obtuse, base broadly cuneate to rounded, blade coriaceous, dark green adaxially and grayish green abaxially, glabrous on both sides; midrib concave adaxially and prominent abaxially; secondary veins 4–6 on each side, inconspicuous on both sides. Stipules interpetiolar, 1.5–2.5 mm long, broadly ovate or triangular, apex acuminate, margin toothed with tipped colleters, glabrous or sometimes fimbriate. Inflorescences terminal, compound-cymose; rachis terete; peduncles 6.0–15.0 cm long; bracts ovate-lanceolate to lanceolate, 0.5–3.0 cm long; bracteoles lanceolate, 1.0– 1.5 mm long. Flowers heterostylous, subsessile, pedicels 0–0.5 mm long. Hypanthium ca. 1.0 mm long, obconic-campanulate, glabrous; sepals 4, ca. 1 mm long, triangular, glabrous. Corolla white or purplish on the margin of corolla lobes, infundibuliform, tube 4.2–5.2 mm long, glabrous abaxially, densely pubescent at throat; lobes 4, ca. 3.0 mm long, ovate. Stigma bilobed, ca. 1.0 mm, clavate. Ovary 2 - celled, ovules numerous on axile placentas. Stamens 4, anthers oblong, ca. 1.0 mm long, oblong-lanceolate. Long-styled flower: stamens included, adnate to the middle part of corolla tube; filaments ca. 1.0 mm long; styles exserted, ca. 6.0 mm long. Short-styled flower: stamens exserted, adnate to throat of corolla tube; filaments ca. 2.0 mm long; styles included, ca. 3.0 mm long. Fruits capsular, ca. 2.0 mm in diameter, subglobose or oblate globose, dehiscent at apex and then septicidally along the ventral suture. Seeds 0.5–0.7 mm long, numerous, angular, testa black, reticulate.

Phenology.

Flowering occurs from March to June, and fruiting from July to January of the following year.

Etymology.

The specific epithet refers to the fact that the species is growing in the south of the Guangxi Zhuang Autonomous Region. Its Chinese name is “ 桂南耳草 ” (Guì Nán Ěr Cǎo).

Distribution and habitat.

Up to now, Hedyotis austroguangxiensis is known from Chongzuo City and Fangchenggang City of the Guangxi Zhuang Autonomous Region; it grows mainly on roadsides or wet rocks under secondary forests at an elevation of 800–1100 m. Main associated species are Selaginella doederleinii Hieron. ( Selaginellaceae ) and Blechnopsis orientalis (L.) C. Presl ( Blechnaceae ).

Palynology.

The pollens of the new species are monads, isopolar and spheroidal, with 3 - colporate apertures, the tectum is double microreticulate, with a psilate suprareticulum and a microechinate infrareticulum. The pollen size is 21.7 (20.2–22.7) × 20.6 (19.5–21.4) μm with P / E value of 1.05 in long-styled flower (Fig. 5 A – C View Figure 5 ) and 23.3 (21.1–24.3) × 22.5 (21.3–24.1) μm with P / E value of 1.04 in short-styled flower (Fig. 5 D – F View Figure 5 ).

Additional specimens examined.

CHINA • Guangxi Zhuang Autonomous Region: Chongzuo City , Ningming County, 28 Oct 2020, 21°40'22.476"N, 107°29'09.218"E, 1066.52 m a. s. l., Ming-Deng Yuan & Yi-Da Xu YS 391 ( IBSC) GoogleMaps ; • ibid., Aidian Town, Luxu Village, Gongmu Mountain , 14 Mar 2010, Yu-De Peng, Ying-Feng Huang, Cui-Hong Lu 21786 ( GXMG) GoogleMaps ; • ibid., Tongmian Town, Kunan Village, Liangling , 21°42'33.76"N, 107°31'24.23"E, 951 m a. s. l., 28 May 2013, Dong-Xin Nong, Hai-Feng Ceng, Wei Liu 451422130528052 LY ( GXMG) GoogleMaps ; • ibid., 7 Jan 2020, Ming-Deng Yuan et al. YS 99 ( IBSC) GoogleMaps ; • ibid., 14 Jun 2020, Ming-Deng Yuan, Guo-Bin Jiang YS 340 ( IBSC) GoogleMaps ; • ibid., short-styled flower, 24 Apr 2021, Ming-Deng Yuan & Yi-Da Xu YS 431 ( IBSC) GoogleMaps ; • Fangchenggang City, Fangcheng District , under thick forest, on the hill, 23 Mar 2010, Shiwandashan Collection Team 2189 ( IBK) .

Conservation status.

So far, the subpopulations of Hedyotis austroguangxiensis exceed 4 based on the information from specimens and our field expedition, and more than 600 mature individuals have been found in the field ( AOO 16 km 2, EOO 91 km 2). According to the criteria D 1 of the IUCN Red List Categories and Criteria ( IUCN 2024), the species can be assessed as “ Vulnerable ”. However, this species is widely distributed and may also be found in neighboring countries like Vietnam and Laos. In addition, it has not found any medicinal and ornamental values yet. We thus recommend evaluating it as Least Concern ( LC).