Ixeridium nujiangense Ze H. Wang, 2024

Wang, Ze-Huan, Zhong, Qian-Qian, Li, Yong-Liang, Xu, Jia-Ju & Sun, Qing-Wen, 2024, Ixeridium nujiangense (Crepidinae, Cichorieae, Asteraceae), a new species from southwest Yunnan, China, PhytoKeys 244, pp. 163-174 : 163-174

Ixeridium nujiangense Ze H. Wang sp. nov.

Figs 2 , 4

Type.

China, Yunnan Province, Lincang City, Yongde County, Xiaomengtong Town, Banlao Village , along the bank of Nujiang River , 24 ° 15 ' 19.70 " N, 99 ° 07 ' 03.02 " E, alt. 541 m, 25 Feb 2024, Wang Zehuan & Li Yongliang wzh 20240201 (holotype: KUN!, isotypes: KUN!, GTZM!) .

Diagnosis.

Ixeridium nujiangense is morphologically most similar to I. malingheense but can be distinguished by the following traits: basal leaves usually pinnatisect or pinnately divided, with only a few entire leaves (vs. basal leaves all entire), cauline leaves lanceolate to linear-lanceolate, with upper leaf base attenuated, not clasping (vs. cauline leaves oblong or narrowly elliptical, with upper leaf base auriculately clasping), corolla tube ca. 1 / 5 of the corolla length (vs. corolla tube ca. 1 / 3 of the corolla length), anthers pale brown (vs. anthers yellow), achenes 2.9–3.1 mm in length (vs. achenes 2.5–2.6 mm in length), beak ca. 1 / 3 of the achene length (vs. beak ca. 1 / 6 of the achene length).

Description.

Perennial herbs, 17–37 cm tall, glabrous totally, with white latex. Roots fibrous and densely shoot-bearing, fleshy, up to 0.6 cm in diameter. Stems erect, slender, often branched near the base or below the middle. Leaves glabrous, green on the upper surface and pale green on the lower surface, margin entire or with sparsely slender teeth. Basal leaves rosulate, persistent at anthesis, blades 1.5–5.5 × 0.5–1 cm, entire, pinnatisect or pinnately divided, petioles 6.2–7.5 cm long. Terminal lobes of divided leaves 1.1–3 × 0.3–0.6 cm, ovate, elliptic to narrowly lanceolate, apex obtuse, acute to acuminate, base slightly attenuate; lateral lobes 1–4, concentrated at the lower and middle portions of the leaf, the lower lobes smaller and serrate, the middle lobes larger, elongated or obliquely triangular, gradually tapering towards the acuminate apex. Cauline leaves 3–4, blades lanceolate to linear-lanceolate, 1.3–9.4 × 0.1–0.3 cm, apex acute to acuminate, base attenuate, margin entire and with / without sparsely slender ciliate teeth or serrate lobes at the base. Synflorescence corymbiform, with numerous capitula; capitula with 5 (– 6) florets, base with slender, long peduncle. Bracts linear-lanceolate, up to 7 mm long. Involucre narrowly cylindrical, ca. 5–6 mm long. Phyllaries in two series, glabrous; outer phyllaries broadly ovate, 0.3–0.5 × 0.5 mm, apex obtuse and purplish-brown; inner phyllaries 5, linear-lanceolate, 4.8–5.9 × 0.5–0.9 mm, green on both sides, with transparent membranous margins, apex obtuse and purplish-brown. Receptacle flattened, glabrous, alveolate. Florets 5 (– 6), ligulate, yellow, corolla 5.9–8.1 mm long, tube 1.0– 1.9 mm long, pale yellow, ligules ca. 4.9–6.2 × 1.5–2.1 mm; anthers brown, anther tube 1.8–1.9 mm long; ovary ellipsoid, style ca. 5 mm long. All achenes uniform in shape, pale brown, narrowly fusiform, slightly compressed, 2.9–3.1 mm long, with 3 fine ribs on each side, apex attenuate to a slender beak approximately 0.9–1.1 mm in length. Pappus straw-colored, ca. 3 mm long, 1 - seriate, scabrid.

Distribution and habitat.

Ixeridium nujiangense is currently known from two locations in Yongde and Zhenkang Counties, Yunnan, China. This species thrives on the banks of the Nujiang River, which are exposed during the dry season, at an elevation of ca. 540 m. Lotus corniculatus L. ( Fabaceae ) is the primary associated species, sharing the barely vegetated riverbank terrain with I. nujiangense .

Phenology.

Flowering and fruiting occur from December to March.

Etymology.

The specific epithet ‘ nujiangense ’ is derived from the name of the Nujang River along whose banks the type locality is situated.

Vernacular name.

Simplified Chinese: 怒江小苦荬; Chinese Pinyin: Nùjiang Xiǎokǔmǎi.

Additional specimens examined.

China, Yunnan Province, Lincang City, Zhenkang County, Mengpeng Town, Yakou Village , along the bank of Nujiang River , 24 ° 14 ' 08.11 " N, 99 ° 07 ' 03.02 " E, alt. 537 m, 25 Feb 2024, Wang Zehuan & Li Yongliang wzh 20240202 ( KUN!, GTZM!) .

Figures

Figure 2. Comparison of the morphological characteristics between Ixeridium nujiangense (A 1 – K 1) and I. malingheense (A 2 - K 2). A plants B lower cauline leaves C middle cauline leaves D upper cauline leaves E basal leaves F base of middle cauline leaves G capitula in front view H capitula in back view J florets K achenes.

Figure 4. Ixeridium nujiangense sp. nov. A – B habitat C – D plants E fleshy root F intertwined roots and basal leaves G basal leaves H lower cauline leaf I middle cauline leaf J upper cauline leaf K lower part of middle cauline leaf L capitulum in front view M capitulum in back view N involucre O floret P achene with pappus.