Ajania flavida Long Wang, 2024

Chi, Xiao-Rui, Wu, Hai-Song & Wang, Long, 2024, Ajania flavida (Asteraceae, Anthemideae), a distinct new species from southwestern China, PhytoKeys 239, pp. 205-213 : 205

Ajania flavida Long Wang sp. nov.

Figs 1 , 3 , 4

Diagnosis.

Ajania flavida is distinct in A. sect. Ajania in being shrubs of 1-2 m in height and having creamy yellow florets. It is superficially similar to A. ramosa in A. sect. Phaeoscyphus , but can be easily distinguished by the plant habit (shrub vs. subshrub), plant height (1-2 m vs. 40-60 cm), leaf division (2-pinnatisect vs. 1(-2)-pinnatisect), size of the involucres (ca. 3 mm vs. 4-5 mm in diameter), color (creamy yellow vs. yellow) of the florets and margins (whitish scarious vs. brown scarious) of the phyllaries.

Type.

China. Xizang: Jomda, Tongpu , 31°35'58.77"N, 98°22'44.19"E, rocky slopes along river, 3212 m a.s.l., 6 September 2019 (fl.), Long Wang, Xin-qiang Guo & You-pai Zeng 3428 (holotype: IBSC; isotypes: IBSC). Fig. 4 .

Description.

Shrubs, 1-2 m tall. Old branches gray-black, sparsely sericeous or glabrescent, with densely leafy tips; flowering branches robust, densely grey powdery-sericeous, especially in upper parts and on peduncles. Proximal leaves of flowering branches withered during anthesis. Middle leaves of flowering branches shortly petiolate; petiole 1-2 cm long; leaf blade ovate in outline, 7-10 cm long, 6-7 cm wide, adaxially dark green, grey sericeous, abaxially greyish, densely grey sericeous, 2-pinnatisect; lobes usually 5, narrowly oblong, lateral 1 or 2 pairs 3-4 cm long, 1.0-2.5 cm wide, distal ones 4-6 cm long, 2-3 cm wide, 1-pinnatisect; segments 2-7, lanceolate to narrowly oblong, lateral 1-3 pairs 4-20 mm long, 2-4 mm wide, distal ones 2-4 cm long, 2-5 mm wide. Distal leaves of flowering branches shortly petiolate to sessile; petiole, when present, 0.5-1.5 cm long; leaf blade ovate to linear in outline, progressively smaller upward, 1-pinnatisect to undivided. Synflorescence a terminal compound flat-topped panicle, 5-10 cm in diameter. Capitula many, erect. Involucres campanulate, ca. 3 mm in diameter, outside straw-colored, glossy; phyllaries in 4 rows, outer ones ovate to triangular-ovate, 1.0-1.2 mm long, 0.8-1.0 mm wide, abaxially densely whitish sericeous, apex acute, middle ones oblong to elliptic, 1.5-2.0 mm long, 1.0-1.2 mm wide, abaxially whitish sericeous, margin narrowly to broadly whitish scarious, apex rounded, inner ones narrowly oblong to oblong, 1.5-2 mm long, 0.6-1 mm wide, abaxially slightly whitish sericeous, margin broadly whitish scarious, apex rounded to obtuse. Florets creamy yellow, exterior with several sessile glands. Marginal female florets 9-11, 2-2.8 mm long; tube 0.4-0.7 mm long; corolla narrowly tubular, 0.8-1.1 mm long, apically 4-5-denticulate. Central disk florets many, 2.8-3.2 mm long; tube 0.8-1.2 mm long; corolla broadly tubular, 0.9-1.2 mm long, apically 5-denticulate, incurved; style 1.1-1.3 mm long; branches creamy yellow. Achenes (immature) 0.6-0.8 mm long, obconic. Pappus absent.

Distribution and habitat.

Ajania flavida is currently known only from western Sichuan ( Baiyü, Batang, Dêgê) and eastern Xizang (Gonjo, Jomda), China (Fig. 5 ). It grows on rocky slopes in gorges at elevations of 3075-3800 m above sea level.

Etymology.

The specific epithet ' flavida ' refers to the creamy yellow florets of this new species.

Phenology.

Flowering in September; fruiting in October.

Vernacular name.

川藏亚菊 (Chinese pinyin: chuān zàng yà jú).

Conservation status.

Ajania flavida is currently known only from eight collections made from western Sichuan ( Baiyü, Batang, Dêgê) and eastern Xizang (Gonjo, Jomda), China. It usually grows on rocky slopes along roadsides in the gorges, and its habitat is at risk through human activities, such as overgrazing and road construction (Wang, pers. obs.). The Extent of Occurrence (EOO) and the Area of Occupancy (AOO) are calculated to be 7516.23 km2 and 32 km2, respectively. According to the IUCN Red List Categories and Criteria ( IUCN 2012, 2022), this species should be categorized as Vulnerable (VU): B1ab(iii)+2ab(iii).

Notes.

Two collections of Ajania flavida , viz. D. E. Boufford et al. 36429 (F, PE) and M. Z. Wen & S. C. Xiao Xiang157 (CDBI), have been previously misidentified as A. variifolia C. C. Chang, a species occurring in Heilongjiang, Hubei and Shaanxi in China. Ajania flavida is readily distinguished from A. variifolia in being a shrub (vs. subshrub), 1-2 m (30-60 cm) tall and having leaf blades 2-pinnatisect (vs. 1-pinnatisect), involucres ca. 3 mm (vs. 4-5 mm) in diameter, and margins of phyllaries whitish (vs. brown) scarious.

It is noteworthy that the identity of Ajania ramosa needs to be further determined. According to our observations on both herbarium specimens and living plants in the wild, this species is poorly defined. It may encompass elements of multiple species in the genus.

Additional specimens examined

(paratypes). China. Sichuan: Baiyü, Jinsha xiang, by the Yangtze River , among scrub in valley, 3157 m, 31°16'42.66"N, 98°49'03.32"E, 25 July 2010, Kham Exped. 10-0662 (PE); Batang, Lieyi xiang, Yidun, on rocks along road, 3400 m, 19 September 1984, M. Z. Wen & S. C. Xiao Xiang 157 (CDBI); Dêgê, Gongya township , road (highway 317) from Dêgê to Baiyu above E side of bridge over Jinsha Jiang ( upper Chang Jiang ) connecting Sichuan and Xizang (Tibet), downstream from confluence of Serqu He (Serqu River), dry slope above Jinsha Jiang with spinescent shrubs (ca. 1 m tall) of Sophora , Rosa , and Caragana , 3075 m, 31°37'40"N, 98°35'28"E, 14 August 2006, D. E. Boufford et al. 36429 (F, PE); Dêgê, Keluodong xiang, on the way from Keluodong to Damagou, 1 August 1951, Y. W. Tsui 5942 (PE) . Xizang: Gonjo, Waba [Zeba xiang], grassland on mountain slopes, 3800 m, 20 August 1976, Qinghai-Xizang Vegetat. Exped. 9655 (PE); Jomda , near Jomda township , on cliffs in valley, 3195 m, 31°31'39.40"N, 98°14'31.03"E, 10 August 2010, Kham Exped. 10-1622 (PE); Jomda, Tongpu xiang, terrace in valley, 3300 m, 25 August 1973, HNWP Xizang Exped. 2195 (HNWP) .

Figures

Figure 1. Specimens of Ajania flavida sp. nov. previously misidentified as A. ramosa or A. variifolia A China, Sichuan, Dege, D. E. Boufford et al. 36429 (PE) B China, Sichuan, Baiyue, Kham Exped. 10 - 0662 (PE) C China, Xizang, Jomda, HNWP Xizang Exped. 2195 (HNWP) D China, Xizang, Jomda, Kham Exped. 10 - 1622 (PE).

Figure 3. Ajania flavida sp. nov. in the wild (China, Xizang, Jomda) A habitat B habit C basal leaves (adaxial surface) D synflorescence (top view) E synflorescence (side view) F phyllaries (abaxial surface) G marginal female florets H central disk florets. Photographs by Long Wang.

Figure 4. Holotype sheet of Ajania flavida sp. nov.

Figure 5. Distribution of Ajania flavida sp. nov. (Black dot).