Hedysarum cuonanum P.L.Liu, J.Wen & Zhao Y.Chang, 2017

Liu, Pei-Liang, Wei, Ying, Wen, Jun & Chang, Zhao-Yang, 2017, Recognition of a new species of Hedysarum (Fabaceae, Hedysareae) from China based on morphological and molecular evidence, Phytotaxa 295 (3), pp. 237-245 : 241

Hedysarum cuonanum P.L.Liu, J.Wen & Zhao Y.Chang , sp. nov. ( Figs. 3–4 )

TYPE: — CHINA. Tibet: Cuona County, Langpo Xiang, near Dongzhang waterfall, 3588 m, 27°46′37.90″ N, 91°58′34.06″ E, 11 August 2013, FLPH Tibet Expedition, Y.S. Chen, Z.Y. Chang, M. Deng, F.Q. Zhang, Y. Xu, W.T. Jin, Q. Yuan 13-0948 (Holotype, WUK!, barcode WUK0533824; Isotypes, PE!, barcodes 01992086, 01992087, 01992157, 01992158) .

Diagnosis: —This new species is similar to H. xizangense , but differs by its lanceolate or narrowly elliptic leaflet blade, ovate or lanceolate bracteole about half the length of calyx tube, acute or obtuse standard apex, mucronate keel apex. It also resembles H. longigynophorum , but can be distinguished by its leaflet blade with 13–19 secondary veins on each side, abaxial calyx tooth about 1.5 times as long as the adaxial teeth, standard as long as keel, and elliptic or ovate loment article ( Table 1, Fig. 5 ).

Description: —Perennial herbs, up to 100 cm tall. Stems caespitose, erect or ascending, pubescent when young, soon glabrate. Leaves imparipinnate, alternate, subsessile, 10–15 cm long; stipules connate, opposite to leaves, wide triangular, 1–1.5 cm long, membranous, brown, glabrous, apex shallowly bilobed; rachises sulcate, sparsely pubescent; leaflets 17–25, opposite or alternate; petiolules ca. 1 mm long, pubescent; leaflet blades lanceolate or narrowly elliptic, 20–30 × 5–7 mm, adaxial surface glabrous, with dense minute amber dots, abaxial surface sparsely pubescent along midvein and near margin, with 13–19 secondary veins on each side, base wide cuneate or rounded, apex acute or obtuse, mucronulate. Racemes axillary, exceeding leaves, 16–22 cm long, with 20–25 flowers, peduncles pubescent; pedicel 2.5–4 mm long, pubescent; bracts caducous, ovate, membranous, brown, glabrous, 4.5–5.5 × 1.5–2 mm; bracteoles 2, ovate or lanceolate, brown, acuminate, 1–1.5 × 0.5–0.8 mm; calyx tube campanulate, 2.5–3 mm long, pubescent; calyx teeth 5, pubescent, the two adaxial teeth shortest, 3–4 mm long, close to each other, the two lateral teeth 4–5 mm long, the abaxial tooth longest, 5–6 mm long; corolla purple; standard obovate, 16–17 × 7 mm, apex acute or obtuse, base attenuate; wings 14–15 × 2–3 mm, auricle as long as claw, 2–3 mm long; keels 16–17 × 4–5 mm, apex with a mucro, auricle triangular, ca. 1 mm long; androecium diadelphous, ca. 15 mm long; ovary linear, pubescent, gynophore ca. 2 mm long, style 12–13 mm long. Legume a loment, divided into 1 or 2 articles, with a small beak at apex, stipe 7–9 mm long; articles elliptic or ovate, compressed, 7–13 mm × 5–6 mm, pubescent, with reticulate veins, without wing along margin.

Phenology: ––Flowering and fruiting in August.

Distribution and Habitat: –– Hedysarum cuonanum is now only known from the type location. It grows in grass slope along stream in valley, 3588 m a.s.l.

Etymology: ––The epithet cuonanum is chosen for this new species due to the name of the type location, Cuona (also transliterated as Cona), in Tibet, China.

Notes: –– H. cuonanum is similar to H. xizangense and H. longigynophorum . All these three species have elongated stems, alternate leaves, calyx with 5 teeth, purple corollas, wings with auricle as long as claw, pubescent ovaries and loments with prominent gynophore, loments without wing along margin. With these characters, these three species can be distinguished from the other Hedysarum species in the Himalaya ( Ohashi & Tateishi 1975, Li & Ni 1985, Xu 1998, Xu & Choi 2010). Whereas H. cuonanum is supported as a new species based on phylogenetic evidence ( Figs 1–2 ) and morphological distinctions ( Fig. 5 , Table 1).

Figures

FIGURE 1. Bayesian tree based on combined nuclear ETS and ITS sequences. The Bayesian posterior probabilities are below the branches, and the maximum parsimony (left) and maximum likelihood (right) bootstrap supports are above the branches.A dash indicates a branch that is not found in the maximum likelihood tree.

FIGURE 2. Bayesian tree based on combined plastid psbA-trnH, trnC-petN, petN-psbM sequences. The Bayesian posterior probabilities are below the branches, and the maximum parsimony (left) and maximum likelihood (right) bootstrap supports are above the branches.

FIGURE 3. Holotype of Hedysarum cuonanum.

FIGURE 4. Living plant of Hedysarum cuonanum. A, in the habitat; B, upper part of the plant.

FIGURE 5. Morphology comparison of leaflets, flowers and legumes of Hedysarum cuonanum, H. longigynophorum and H. xizangense. A, H. longigynophorum (from Chang et al. 2013206, WUK, except for the loment which is from Xu et al. Xu130346, WUK); B, H. cuonanum (from Holotype); C, H. xizangense (from Chen et al. 13-0886, WUK). For specimen details, see Appendix. le, leaflets; b, bracteoles; c, calyx; s, standard; w, wings; k, keels; a, androecium; o, ovary; lo, loment.