Polygonatum binatifolium S.R. Yi et H.X. Zhu, 2022

Zhu, Heng-Xing, Huang, Fei-Yi, Chen, Hong-Yuan, Zhang, Hong-Jing, Dai, Qian-Li & Yi, Si-Rong, 2022, Polygonatum binatifolium, a new species of Polygonatum (Asparagaceae) from Guizhou, China, Phytotaxa 549 (2), pp. 247-252 : 248-251

Polygonatum binatifolium S.R. Yi et H.X. Zhu , sp. nov. ( Figs. 1–2 )

Diagnosis:—The new species is most similar to Polygonatum cyrtonema Hua , but differs by its shorter stem (20–50 cm vs. 50–100 cm), much smaller leaves (4–8 × 2.4–4.5 cm vs. 10–18 × 2–7 cm) and lowest two opposite (vs. alternate), perianth 8–12 mm long (vs. 1.8–2.5 cm), filaments ca. 1.0 mm long (vs. 3–4 mm), ovary 1.8–2.2 mm in diam. (vs. 3–6 mm), style 1.5–2.0 mm long (vs. 1.2–1.5 cm), berry red (vs. black) and 5.5–6.5 mm in diam. (vs. 6-12 mm), seed pale yellow (vs. yellowish-white), 2.4–3.0 × 2.0– 2.4 mm (vs. 3.8–5.6 × 2.8–3.6 mm) ( Table 1 ).

Type:— CHINA. Guizhou: Yinjiang County, Mt. Fanjing , N27°54′43″, E108°39′37″, elev. 2, 014 m, on the mossy rocks or tree trunks under forests, 22 May 2020, S.R. Yi 8547 (holotype, KUN; isotype, KUN) .

Perennial herbs, up to 50 cm tall, rhizome tuberous, with many rings, upper tip with hollow round stalk scars. Rhizome 1.5–3.0 cm in diam., with most fibrous roots up to 30 cm long. Stem green, sparsely short glandular hairs, purple pinstripes bottom node, 2.5–4.5 mm in diam.. Two bottom leaves opposite, upper leaves alternate; leaf blade oblongovate to oblong-lanceolate, 4.0–8.0 × 2.4–4.5 cm, with 5–7 veins, adaxially dark green, abaxially pale green, glabrous both sides, apex rounded and obtuse, base broadly cuneate, descending to petiole; petioles 3.0–5.0 mm long, base half clasped; midrib adaxially concave, abaxially raised. Inflorescence axillary with 2–5 flowers or 1–2 flowers no peduncles, peduncles 5.0–8.0 mm long, lower flattened, up to 3.0 mm wide, pedicels rounded, 8–15 mm long, peduncles and pedicels smooth and glabrous; bracts absent. Flowers yellow-green, 8–12 mm long, tube 4.0–5.0 mm in diam., crown 5.0–6.0 mm in diam., tube 5.0–6.0 mm long; inner lobes broadly ovate, 3.4–3.8 ×3.0–4.0 mm, apex obtuse, suberect; outer lobes narrowly ovate-lanceolate, 2.4–2.7 × 3.0–4.0 mm, apex short pointed, volume; perianth lobes all with a pale green midrib. Stamens inserted near middle of corolla tube, filaments very short, ca. 1.0 mm long, anthers arrowhead, 1.6–1.9 mm long. Pistil smooth and glabrous, ovary alar, 1.8–2.2 mm in diam., 2.5–3.0 mm high, style 1.5–2.0 mm long, stigma capitate. Berries globose, red, 5.5–6.5 mm in diam., 3-loculed, 1–3-seeded per locule; seeds ovoid, pale yellow, slightly flattened, 2.4–3.0 ×2.0– 2.4 mm.

Distribution and habitat: —According to present collections, Polygonatum binatifolium was only known from two localities in Guizhou province, i.e., Mt. Fanjing, Yinjiang and Woyangqing, Panzhou. This rare species grows on mossy rocks or tree trunks under forests between 1,900 m and 2, 100 m at elevation. It is considered as Critically Endangered (CR) according to current information and the IUCN Red List criteria ( IUCN, 2019) because it is only found in the area of less than 5 km 2 in Yinjiang and Panzhou. Future fieldwork may expand its distribution area and habitat.

Phenology: —Flowering time is between April and May; fruiting time from September to October.

Etymology: —The specific epithet refers to the opposite state of the lowemost two leaves. The Chinese name is given as “ 基对叶fiffl ”.

Additional specimens examined (paratypes): — CHINA. Guizhou: Panzhou, Woyangqing , N25°59′5″, E104°51′3″, elev. 1, 935 m, on mossy rocks under forests, 24 May 2020, S.R. Yi 8561 (KUN); Panzhou, Woyangqing, N25°59′5″, E104°51′3″, elev. 1, 935 m, on mossy rocks under forests, 16 September 2021, S.R. Yi 9267 (KUN); Yinjiang County, Mt. Fanjing , N27°54′43″, E108°39′37″, elev. 2, 014 m, on the mossy rocks under forests, 9 October 2021, S.R. Yi 9308 (KUN); Panzhou , Yangmazhai [maybe not the real location], N25°58′40.9″, E104°53′44.7″, in the grass, elev. 1, 619 m, 11 July 2014, Ping-zhong Qu 520222140711007LY (GZTM0045437, GZTM0045438) .

Figures

FIGURE 1. Polygonatum binatifolium S.R. Yi et H.X. Zhu. (a). Plant; (b). Rhizome; (c). Inflorescence; (d). Corolla (longisection); (e). Stamen; (f). Pistil.

FIGURE 2. Polygonatum binatifolium S.R. Yi et H.X. Zhu. (a–b). Habitat; (c). Plants; (d–h). Inflorescence; (i). Rhizome; (j–k, m). Flower (longisection); (l). Corolla (transection); (n). Stamen; (o). Pistil.