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

1. Hedyotis jinghongensis M. D. Yuan & R. J. Wang sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3

Type.

CHINA • From Yunnan Province: Dai Autonomous Prefecture of Xishuangbanna, Jinghong City, Jinuo Town , roadside, under thick forest, 21°58'50.29"N, 101°04'21.16"E, ca. 1288 m a. s. l., flowering, short-styled flower, 31 July 2019, Xin-Xin Zhou, Guo-Bin Jiang & Ming-Deng Yuan 1406 ( holotype: IBSC [0858378]; isotype IBSC [0858377]) GoogleMaps .

Diagnosis.

The new species is similar to H. communis W. C. Ko (1974: 578) and H. interrupta G. B. Jiang & R. J. Wang (2021) in having lanceolate to narrowly lanceolate leaves and triangular stipules, but it differs from H. communis by having obvious tetragonal stem, smaller leaves, stipules marginally with 3–6 colleter-tipped linear lobes on each side, and short inflorescences with small flowers (Table 2 View Table 2 ). It is also distinguished from H. interrupta by having small leaves, stipules marginally with 3–6 colleter-tipped linear lobes on each side, and short inflorescences (Table 2 View Table 2 ).

Description.

Perennial herbs, erect, 15–60 (– 80) cm tall. Stem tetragonal, narrowly winged, branched mostly at the upper part, glabrous. Leaves opposite, petioles 2.0–5.0 mm long, glabrous; blade 2.5–9.0 × 0.7–2.0 cm, lanceolate to narrowly lanceolate, apex acuminate to caudate acuminate, base cuneate, blade papyraceous, light green adaxially and grayish green abaxially, glabrous on both sides; midrib depressed adaxially and prominent abaxially, secondary veins 3–7 on each side, distinct on both sides. Stipules interpetiolar, 5.0– 10 mm long, triangular to narrowly triangular, marginally with 3–6 colleter-tipped linear lobes on each side, glabrous. Inflorescences terminal and axillary on lateral branches, 5–20 flowered, cyme or compound cymose; peduncles 0.5–3.0 cm long, tetragonal, narrowly winged, glabrous; bracts 2.0–12.0 mm long, lanceolate or linear. Flowers heterostylous, pedicels 0–2.0 mm long. Hypanthium ca. 1.0 mm long, campanulate, glabrous; sepals 4, 1.0– 1.2 mm long, narrowly triangular, glabrous. Corolla tubular, white; tube 1.7–2.0 mm long, densely pubescent at throat adaxially, glabrous abaxially; lobes 4, 1.8–2.0 mm long, oblong-lanceolate, glabrous abaxially, and pubescence adaxially. Stigma bilobed, ca. 0.5 mm long, clavate. Ovary 2 - celled, ovules numerous on axile placentas. Stamens 4, anthers ca. 0.8 mm long, oblong-linear. Long-styled flowers: corolla tube ca. 2.0 mm long; stamens included, adnate to the middle of corolla tube; filaments ca. 0.8 mm long; styles ca. 3.3 mm long, stigma exserted. Short-styled flowers: corolla tube ca. 1.7 mm long; stamens included, adnate to throat of corolla tube; filaments ca. 1.2 mm long, anthers exserted; styles ca. 2.8 mm long, stigma included or slightly exserted. Fruits capsular, 1.5–2.0 × 2.0– 2.5 mm, subglobose, sepals persistent, glabrous, dehiscent at apex and then septicidally along the ventral suture. Seeds ca. 0.5 mm long, numerous, angular, 0.4–0.6 mm long, testa black, reticulated.

Phenology.

Flowering and fruiting individuals were observed between June and December.

Etymology.

The specific epithet refers to the type locality of this new species, Jinghong City, Dai Autonomous Prefecture of Xishuangbanna, Yunnan Province. Its Chinese name is “ 景洪耳草 ” (Jǐng Hóng Ěr Cǎo).

Distribution and habitat.

Currently, Hedyotis jinghongensis is only known from southern Yunnan Province, China. It grows on roadsides under secondary forests at an elevation of 700–1400 m. The main associated species are Selaginella leptophylla Baker ( Selaginellaceae ), Phyllanthus urinaria Linnaeus ( Phyllanthaceae ), and Sonerila cantonensis Stapf ( Melastomataceae ).

Palynology.

The pollens of the new species are monads, isopolar, with 3 - or 4 - colporate apertures, the tectum is double microreticulate, with a psilate suprareticulum and a microechinate infrareticulum. The pollen size is 25.9 (23.6–28.0) × 24.8 (23.4–26.3) μm with P / E value 1.04, and the shape is spheroidal in long-styled flowers (Fig. 3 A – C View Figure 3 ); the pollen size is 20.0 (17.5–20.2) × 16.9 (16.4–17.1) μm with P / E value 1.18, and the shape is subprolate in short-styled flowers (Fig. 3 D – F View Figure 3 ).

Additional specimens examined.

CHINA • Yunnan: Dai Autonomous Prefecture of Xishuangbanna, Cheli County, Zhalei , under thickets, 1400 m a. s. l., Oct 1936, Qi-Wu, Wang 79170 ( KUN) ; • Jinghong City, Jinuo Town, Longpa Village , under forest, 22°2'N, 101°1'E, 1250 m a. s. l., 02 Aug 1977, Guo-Da Tao 16483 ( HITBC, IBSC) GoogleMaps ; • ibid., 04 Aug 1977, Guo-Da Tao 17845 ( HITBC) GoogleMaps ; • ibid., 21°59'N, 101°40'E, 1250 m a. s. l., 29 Jul 1977, Guo-Da Tao 17850 ( HITBC, KUN) GoogleMaps ; • ibid., 30 Nov. 2018, Xin-Xin Zhou 5469 ( IBSC) GoogleMaps ; • ibid., Mengyang Town , near river, 22°53'N, 100°53'E, 750 m a. s. l., Guo-Da Tao 16799 ( HITBC) GoogleMaps ; • ibid., Guanping Village , roadside, slopes, 22°11'N, 100°52'E, 800 m a. s. l., 17 Aug 1977, Guo-Da Tao 17577 ( KUN, IBSC) GoogleMaps ; • ibid., 10 Nov 2019, Ming-Deng Yuan & Jiang-Ping Shu YS 26 ( IBSC) GoogleMaps ; • ibid., Puwen Town, Dakaihe Village , under forest, 22°35'N, 101°2'E, 14 Aug 1977, Guo-Da Tao 16898 ( HITBC, KUN) GoogleMaps ; • ibid., Mengla County, Mengman Town, Jingpiao Village , 21°37'N, 101°41'E, Investigation Team 25230 ( HITBC) GoogleMaps ; • ibid., Yaoqu Town, Nazuo Village , in miscellaneous wood forest, 21°40'N, 101°36'E, 700–800 m a. s. l., 23 Nov 1974, Zeng-Hong Yang 012484 ( HITBC, KUN) GoogleMaps ; • ibid., Puer City , Jinggu County, 23°24'7.35"N, 100°59'50.87"E, 1224 m a. s. l., 12 Sept 2020, Yan-Xiong Gong G 38 ( IBSC) GoogleMaps ; • ibid., Puer County, Mohei Town, Choushui Village , 23°16'N, 101°10'E, 1300 m a. s. l., 27 Aug 1990, Guo-Da Tao 46403 ( HITBC) GoogleMaps ; • ibid., 09 Nov 2019, Ming-Deng Yuan & Jiang-Ping Shu YS 5 ( IBSC) GoogleMaps ; • ibid., the road along Puer County to Jinggu County , in the dank of the valley, 23°21'N, 100°57'E, 950 m a. s. l., Hong Wang 4805 ( HITBC) GoogleMaps .

Conservation status.

So far, four subpopulations with more than 500 mature individuals have been found in the field ( AOO 40 km 2, EOO 8500 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, many other subpopulations of this species may be found nearby in southern Yunnan or northern Laos. Considering that this species has no economic uses, we recommend evaluating it as Least Concern ( LC).