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Zenodo
2025
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| Accès en ligne: | https://doi.org/10.5281/zenodo.17943040 |
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- <p><i>Dysosma xishuiensis</i> Y. B. Yang, M. T. An & C. H. Yang sp. nov.</p><p>Fig. 2</p><p><b>Diagnosis.</b></p><p><i>Dysosma xishuiensis</i> is morphologically most similar to <i>D. versipellis</i> in its stems (erect, unbranched, glabrous), leaves (alternate, blade suborbicular, to 25–30 cm in diam, palmately lobed), flowers (attached near base of blade, red), but differs by the following characters: leaf abaxial surface, pedicels, and sepals glabrous (vs. pubescent); inflorescences bearing more flowers (8–20 vs. 5–8); larger obovate-oblong petals (2.8–3.4 × 1.5–2.0 cm vs. 2.5 × 0.8 cm); and ovary obpyriform (vs. ellipsoid).</p><p><b>Type.</b></p><p>China • Guizhou, Xishui County, Sanchahe Town, Xishui National Nature Reserve, alt. 975 m, under broadleaf forest beside the stream of Danxia landform, 20 May 2022, <i>Yan-Bing Yang, Cheng-Hua Yang & He Li</i> (holotype: GF!; isotype: GZAC!). • Xishui County, Tucheng Town, Tongyi Village, Xishui National Nature Reserve, alt. 1168 m, in the middle of a mountain under broadleaf forest of Danxia landform, 22 May 2022, Cheng-Hua Yang, He Li & Mao Li C 1031 (isotype: KUN!).</p><p><b>Description.</b></p><p>Herbs, 80–120 cm tall. Rhizomes stout, densely fibrous. Aerial stems erect, pale green, unbranched, glabrous. Leaves alternate; petioles of lower leaves 10–20 cm, upper leaves ca. 3 cm; leaf blade suborbicular, up to 25 cm in diameter, thinly papery, glabrous on both surfaces, abaxially with prominent venation, palmately 5–8 - lobed, lobes deeply divided (ca. 2 / 3 of radius); lobes obovate to obovate-oblong, margins remotely serrate, apex shallowly 3 - lobed or bearing 2–3 mucronate teeth. Inflorescence an 8–20 - flowered fascicle. Pedicels pendulous, slender, glabrous. Flowers dark red, attached near leaf base. Sepals long-elliptic, 1.5–2.0 × 0.5–0.8 cm, glabrous, apex acute. Petals oblong-obovate, 2.8–3.4 × 1.5–2.0 cm, glabrous. Stamens ca. 2 cm; filaments shorter than anthers; anther connective slightly prolonged, glabrous, acute. Pistil ca. 1.5 cm; ovary obpyriform, glabrous; style ca. 0.3 cm; stigma shield-shaped. Berry ellipsoid. Seeds numerous.</p><p><b>Phenology.</b></p><p>Flowering from April to June, fruiting from June to September.</p><p><b>Distribution and habitat.</b></p><p><i>Dysosma xishuiensis</i> is only known from two localities in Xishui County, Guizhou, China, where it grows under the broadleaf forest by the stream or in the middle of a mountain of Danxia landform.</p><p><b>Preliminary conservation status.</b></p><p>Currently, <i>Dysosma xishuiensis</i> is documented exclusively in two discrete populations within Xishui National Nature Reserve. These populations occur in mid-subtropical to warm temperate zones characterized by a humid monsoon climate. The species exhibits a restricted distribution range, with both populations each comprising fewer than 100 mature individuals. In accordance with the International Union for Conservation of Nature (IUCN) Red List criteria B 2 (a, b (iii)) (extent of occurrence <500 km 2, fewer than five locations, continuing decline in habitat quality) and D (population size <250 mature individuals), we propose that <i>D. xishuiensis</i> be designated as Endangered (EN) (IUCN 2022).</p><p><b>Etymology.</b></p><p>The species epithet “ <i>xishuiensis</i> ” refers to the type locality of the new species.</p><p><b>Vernacular name.</b></p><p>The Chinese name is “ xí shuĬ bā jiăo lián ” (习水八角莲).</p>