Dichocarpum yongshanense R.Li, Y.L.Wen & E.D.Liu, 2024

Li, Rong, Wen, Yan-Li, Zhao, Yong-Li, Liu, En-De & Li, Wei, 2024, A new species of Dichocarpum (Ranunculaceae) from northeastern Yunnan, China, Phytotaxa 633 (2), pp. 171-175 : 171-173

Dichocarpum yongshanense R.Li, Y.L.Wen & E.D.Liu , sp. nov. ( Fig. 1 )

Diagnosis: —It is similar to D. hypoglaucum W.T.Wang & P.K.Hsiao in Hsiao & Wang (1964: 327), but it differs from the latter by plant with only two (vs four) basal leaves with membranous (vs herbaceous) and abaxially non-pruinose (vs pruinose) blade, and by flower with pinkish (vs white) sepals.

Type: — CHINA. Yunnan: Zhaotong City, Yongshan County, Huixi township , Desheng village , Niuguntang , subtropical evergreen broad-leaved forest, under forest in mountains, elev. ca. 2030 m, 28°14′55.8″N, 103°53′46.7″E, 30 April 2022, LED 12409 (holotype KUN!; isotype KUN!) .

Perennial herbs, erect, glabrous. Rhizome present, lateral roots dense. Leaves 2, basal, pedately compound, 7–9- foliolate, membranous, green, abaxially non-pruinose; petiole 28–33 cm long; leaf blade 15–20 × 14–18 cm; central leaflet petiolule ca. 3–8 cm long; leaflet blade rhombic-ovate, 9–12 × 4.5–6 cm, base cuneate, apex attenuate, above mid-lower margin with shallow teeth; lateral leaflets 2, petiolule 1.5–4 cm long; leaflet blade obliquely rhombic-ovate, unequal in size, lower leaflets 2.5–6 × 1.5–4 cm, upper leaflet 6.5–11.5 × 3.5–7 cm, margin crenate. Flowering stem ca. 32 cm tall. Inflorescences monochasial, 3–8-flowered; bracts sessile, obovate, 3-lobed, lower bracts 8–12 mm long, upper bracts ca. 1–2 mm long. Flowers 1.2–1.6 cm in diameter. Pedicel 1–2 cm long. Sepals 5, obovate-elliptic, pinkish, 7–10 × 3.5–4.5 mm, apex obtuse. Petal limbs broadly obovate to suborbicular, golden-yellow, ca. 1.3–1.5 mm, apex retuse; claw longer than limb, ca. 2.5 mm long. Stamens numerous, ca. 6.5 mm long; anthers broadly ellipsoid, ca. 0.6 mm long. Pistils 2, connate at base; ovary narrowly obovate, ca. 6 mm long, persistent styles ca. 1.5 mm long. Follicles 2, divaricate, obovoid-lanceolate, ca. 8–10 mm long, beaks ca. 2 mm long. Seeds brown, subglobose, ca. 1 mm in diameter, smooth.

Distribution and habitat: — Dichocarpum yongshanense is currently known only from three sites in the Wumeng mountains in Yongshan County, Yunnan Province, China. It grows in forests at 2000–2200 m elevation.

Conservation status: —The species has been collected only from the type locality and is therefore assumed to be rare. According to guidelines for using the IUCN red list categories and criteria ( IUCN Standards and Petitions Committee 2022), it is considered as ‘Endangered’ (EN) using the criteria set out by IUCN as its known area of occupancy is less than 500 km 2 (criterion B2) and the total population size is estimated to be smaller than 2500 mature individuals (criterion C).

Phenology: — Dichocarpum yongshanense was observed with flowers in April to May, and fruits in May to June.

Etymology: —The specific epithet of the new species refers to its type locality.

Vernacular name: —‘ 永ě人ṪAE ’ (Yong Shan Ren Zi Guo) in Chinese.

Additional specimens examined (paratypes): — CHINA. Yunnan: Zhaotong City, Yongshan County, Tuanjie township , Sutian village , Sanjiangkou , subtropical evergreen broad-leaved forest, under forest in mountains, elev. ca. 2100 m, 28°14′53″N, 103°53′41″E, 11 May 2019, Wei Li 1021 ( KUN!) ; Huixi township, Desheng village, Niuguntang , subtropical evergreen broad-leaved forest, under forest in mountains, elev. ca. 2050 m, 28°14′51.1″N, 103°53′42.6″E, 30 April 2020, Wei Li 1882 ( KUN!) ; Tuanjie township, Sutian village, Sanjiangkou , subtropical evergreen broad-leaved forest, under forest in mountains, elev. ca. 2150 m, 28°14′52.6″N, 103°53′45.5″E, 26 May 2021, Wei Li 2334 ( KUN!) .

Figures

FIGURE 1. Dichocarpum yongshanense. A. Habit. B. Flower.C. Sepal. D. Petal. E. Stamen. F. Pistils. G. Follicles. Drawn by Ling Wang from the holotype.