Youngia hangii T. Deng, D.G. Zhang, Qun Liu & Z.M. Li, 2021

Liu, Qun, Huang *, Gui-Yun, Zhang, Dai-Gui, Zhang, Jian-Wen, Deng, Tao & Li 1, Zhi-Min, 2021, Youngia hangii (Asteraceae, Crepidinae), a new species from Hubei, China, PhytoKeys 182, pp. 27-38 : 27

Youngia hangii T. Deng, D.G. Zhang, Qun Liu & Z.M. Li sp. nov.

Type.

China. Hubei: Wufeng County, Renheping , 30°06'27"N, 110°16'31"E, karst cave of karst topography, 500-800 m alt., 5 August 2018, Daigui Zhang & Qun Liu HAC 001 (holotype KUN (KUN1511675); isotypes KUN (KUN1511676), JSU (HHE 3256)) .

Description.

Herbs, perennial, 20-35 cm tall. Taproot straight or slightly oblique, fleshy, with lateral roots (Fig. 2D ). Stems erect, branched from the base, with sparse white simple hairs; stem base ribbed, with 1 or 2 leaves similar to basal leaves. Basal leaves crowded at the caudex base; petiole 2-3 cm long; blade oblanceolate, 6-18 × 2-4 cm, both surfaces short pubescent with white hairs 0.1-0.3 mm long (pubescence more evident on veins), bipinnate to pinnatifid, apical lobe halberd-shaped, apex acute-acuminate, margin deeply lobed; lateral lobes 5-10 pairs, opposite or slightly skewed, irregularly halberd-shaped (lateral lobes tapering to the base, serrate, lowermost lobes narrowly triangular), often with 1-3 pairs of triangular or oblique-ovate lobes between lateral lobes. Synflorescence corymbiform; capitula 7-10. Involucre ampullate, 3-4 mm long, 3 mm in diameter. Phyllaries in 4 rows, greyish-green; outer phyllaries 5-7, ovoid-triangular, ca. 1 × 1 mm, apex acute; inner phyllaries 7-9, lanceolate, 2-4 × 0.5-1 mm, margin white-membranous, apex acute; florets 8-10, ligules 4-6 × 1-2 mm, teeth 0.2-0.4 mm long, tube 3-4 mm; anther tube ca. 2.5 mm long; style branches ca. 0.5 mm long. Outer achenes black, fusiform, 2 mm long, apex attenuate to shortly beaked and expanded again into the pappus disc; ribs 12-14; pappus white, bristles rough, 3 mm long; inner achenes similar to the outer ones, 2.5 mm long.

Phenology.

Flowering and fruiting April to October.

Vernacular name.

五峰黄鹌菜, wǔ fēng huánɡ ān cài in Chinese Pinyin.

Etymology.

The species epithet honours Prof. Hang Sun (b. 1963), a Chinese botanist who has conducted research on plant taxonomy, floristics, biogeography and evolutionary biology and inspired many people through his work. He has also given a lot of support to the plant research work in Hubei.

Distribution and habitat.

Youngia hangii is known only from the type locality, Renheping in Wufeng Xian, Hubei, China; 500-1000 individuals are known along the edge of some small caves at the base of the karst hillside (Fig. 2A, B, C ); at altitudes of 500-800 m.

Morphological assessment.

Morphological characteristics suggest that Y. hangii is related to Y. rubida and Y. heterophylla owning 10-25 florets and resembles Y. rosthornii with bipinnately deeply partite leaves. The achenes of Y. hangii and Y. rubida are attenuated into a short beak, which is widened into the pappus disc. Several unique features including the shape, lobes and size of the leaves, the leaves with white simple hairs (Fig. 2E, F, G ; Fig. 3F, G ), phyllaries, number of florets and achenes differentiate Y. hangii from Y. rubida and Y. heterophylla (Table 1 ).

Phylogenetic analysis.

The Bayesian tree showing PP support, ML bootstrap (LP) and MP bootstrap (BP) values for each clade are presented in Fig. 1 . The species in clade Ι form a monophyletic group with PP = 0.97, but LP are with weak support and BP are in conflict with PP and they were instead with “-”, respectively in Fig. 1 . Youngia hangii is nested within Clade I as sister to Y. rubida with strong support (PP = 1, LP = 83, BP = 88).

Figures

Figure 1. Bayesian consensus tree of Youngia hangii and related species. The BP tree is constructed, based on the combined matrix of ITS and rps 16 sequences. Numbers below branches are ML bootstraps and MP bootstraps and numbers above branches indicate Bayesian posterior probability. Youngia hangii is shown in bold.

Figure 2. Youngia hangii T. Deng, D. G. Zhang, Qun Liu & Z. M. Li A habitat B population C habit D root E stems F, G leaves H-J capitula K, L floret (A-E, H-J Photos by D. F. Zhang F, G, K, L Photos by Qun Liu D, E, J-M HAC 001 (KUN )).

Figure 3. Youngia hangii T. Deng, D. G. Zhang, Qun Liu & Z. M. Li A, B capitula C floret D habit E leaf with hairs F achene (drawing by Jianing Yang).