Ixeridium malingheense Z.Li & Q.Xu

Xu, Qin, Yang, Long, An, Mingtai, Yu, Jianghong, Liu, Feng & Li, Zhi, 2024, Ixeridium malingheense (Asteraceae), a new species from southwestern Guizhou, China, Phytotaxa 645 (2), pp. 163-171 : 167

Ixeridium malingheense Z.Li & Q.Xu , sp. nov. Figs. 3 & 4 Ḣ岭河小äffi

Type: — CHINA. Guizhou Province, Xingyi City, Ma-ling River Canyon , growing on exposed limestone along river banks in the canyon, 104°59′26″ E, 25°2′43″ N, alt. 890 m, 28 March 2023, Z. Li & Q. Xu LZ-XQ2023032801 (holotype GZAC!, isotypes GZAC!).

Diagnosis: — Ixeridium malingheense is morphologically close to I. yunnanense but differs from the latter by its basal leaves 18–34 × 5–13 mm, leaf blade spatulate or long-spatulate, petiole long, ca. 30–55 mm, outer phyllaries 1-seriate, achene brown or pale brown, subfusiform, compressed, ca. 2.0–3.0 × 0.5–1.0 mm, with a beak 0.4–0.6 mm long, and flowering period from March to May.

Perennial herb, 6–25 cm tall, stem erect, slender. Roots fibrous and spreading. Branches diverging from the middle or basal half, sparse, glabrous, distantly leafy. Basal leaves crowded, usually present at anthesis, long-spatulate or spatulate, margin entire, apex acute and often mucronate, 18–34 × 5–13 mm, undivided and semi-amplexicaule, laurel-green adaxially, light pink-green abaxially, base attenuated into a petiole-like portion, petiole 30–55 mm long. Cauline leaves few, 2–5; undivided, linear-subulate and bract-like, petiolate, 7–40 × 3–7 mm, smaller than basal leaves, base semi-amplexicaule and slightly clasping, reduced, linear, and subsessile along the stem. Synflorescence corymbiform to paniculiform-corymbiform, with 7–32 capitula. Capitula liguliflorous with 6–7 florets, radiating, peduncle capillaceous. Involucre narrowly cylindrical, 5–6 mm, phyllaries abaxially glabrous; outer phyllaries 5–7, ovate, ca. 1 mm long, apex acute, calyculate; inner phyllaries 5–6, linear-lanceolate, 4–6 mm long, white-margined, thick-keeled towards base, apex acute, minutely ciliolate at the apex. Florets ligulate 6–7, yellow, linear, apex 5-lobed, corolla 9–10 mm long, tube 2.5–3.5 mm long. Anthers 2.0– 2.5 mm long, filaments 2.0– 2.2 mm long, appendage cylindrical, apex obtuse. Style branches ca. 1.4 mm long, papillate. Achenes brown or pale brown, subfusiform, compressed, 2.0–3.0 × 0.5–1.0 mm, apex attenuate into a slender 0.4–0.6 mm beak, ca.10 equal ribs, none winged, ± glabrous. Pappus straw-coloured bristles, 2.0–3.0 mm, 1-seriate, persistent.

Etymology: —The epithet indicates the type locality, Ma-ling River Canyon, Xingyi City, Guizhou Province, China. The locality name is rendered as ‘Malinghe Canyon’ in Chinese pinyin.

Distribution and ecology: —The new species is currently only known from Xingyi City, Guizhou Province, China, at an altitude of ca. 890 m. It grows on limestone near rivers.

Phenology: —Flowering from March to May, fruiting from March to June.

Vernacular name: —Ḣ岭河小äffi, mǎ lǐng hé xiǎo kǔ mài in Chinese Pinyin.

Conservation status: — Ixeridium malingheense is currently found only in the Ma-ling River Canyon, which is the type locality, and only one population of approximately 40 plants has been observed to date, making the population extremely rare. Owing to the lack of additional local studies, its status is considered “Data Deficient” (DD) according to the IUCN Red List Categories and Criteria ( IUCN 2022). The area is, however, a scenic spot, and habitat disturbance by human activities, such as tourism, maintenance, building of roads and walking trails, may have a negative impact on the species, potentially fatally impacting the survival of its small population. This species, additionally, only grows on limestone near water, where its growth environment is easily affected; the conservation status of this species is, therefore, of great concern.

Figures

FIGURE 3. A–I. Ixeridium malingheense Z.Li & Q.Xu, sp. nov.: A. habitat (Ma-ling River Canyon, Xingyi City, SW Guizhou, CHINA); B. Caespitose plants in the wild; C. habit; D. capitulum (top view); E. capitula (showing involucre); F. involucre; G. spatulate basal leaves with long petiole; H. capitula floret; I. achene with pappus. Photos by Zhi Li (A–B), Feng Liu (C–D, H), Long Yang (E–F, I), Qin Xu (G).

FIGURE 4. Holotype of Ixeridium malingheense Z.Li & Q.Xu, sp. nov. Photo by Qin Xu.