Saussurea zayuensis Y. S. Chen, 2015

Chen, You-Sheng & Yuan, Qian, 2015, Twenty-six new species of Saussurea (Asteraceae, Cardueae) from the Qinghai-Tibetan Plateau and adjacent regions, Phytotaxa 213 (3), pp. 159-211 : 190-192

17. Saussurea zayuensis Y. S. Chen , sp. nov. ( Fig. 17 )

Type:— CHINA. Xizang: Zayü County, the pass of Sangjiu to Ridong , in moss on rocky slopes, 28°47 ʹ N, 97°37 ʹ E, 3660 m, 16 September 2012, FLPH Tibet Expedition 12-1349 (holotype PE; isotypes PE) .

Herbs perennial, 10–16 cm tall, shortly stemmed, usually caespitose. Caudex stout, usually branched at ground level, covered with remains of petioles. Stems several, unbranched or branched, purplish, sparsely arachnoid tomentose to glabrescent. Rosette leaves petiolate; petiole 2–3 cm long; leaf blade narrowly elliptic to lanceolate, pinnately lobed, 4–11 cm long, 0.5–2 cm wide, adaxially dull green, glabrous, abaxially grayish white to light green, shortly tomentose, margin coarsely toothed, apex obtuse and mucronate; lateral lobes 4–8 pairs, ovate or semiorbicular, apex mucronate. Capitula solitary or 2–5 in racemose corymbiform synflorescence, in center of leaf rosette; peduncles distinct, 2–6 cm long, purplish, sparsely arachnoid tomentose to glabrescent. Involucre campanulate, 10–15 mm in diameter, 12–15 mm high. Phyllaries in ca. 5 rows, apex and margin blackish, villous; outer and middle phyllaries narrowly ovate-elliptic, 7–13 mm long, 2–3 mm wide, apex acuminate; inner phyllaries linear, 12–13 mm long, 1–1.8 mm wide, apex acuminate. Receptacle bristles to 4–4.5 mm long. Corolla purple, 13–15 mm long, tube 7–8 mm long, limb ca. 6–7 mm long, lobes ca. 3 mm long. Anthers ca. 7 mm long including tails; tails lanate, ca. 1 mm long. Achenes cylindroid, ca. 3 mm long, ribbed. Pappus pale brown; outer bristles ca. 3 mm long, scabrid; inner bristles 11–12 mm long, plumose.

Distribution and habitat:— Saussurea zayuensis is currently known only from Zayü County, southeastern Xizang. It grows in moss on rocky slopes at altitudes of 3660–4000 m.

Phenology:—Flowering and fruiting from August to September.

Etymology:—The specific epithet is derived from its type locality, Zayü County. Chinese name: ḄḆṈLẄ. Additional specimens examined (paratypes):— CHINA. Xizang: Zayü County, the pass of Sangjiu to Ridong,

3660 m, 16 September 2012, FLPH Tibet Expedition 12-1373 ( PE) ; same locality, meadows, 4000 m, 16 September 2012, FLPH Tibet Expedition 12-1348 ( PE) .

Discussion:—No species are shown to be closely related to S. zayuensis in our molecular tree. It is similar to S. retroserrata Chen et al. (1981: 97) in its habit, pinnately lobed leaves, capitula size and number, phyllaries blackish purple, and pappus pale brown, but differs by its stems 10–16 cm tall (vs. 30–40 cm tall), leaf blade pinnately lobed (vs. retrorsely serrate to retrorsely pinnately lobed), and phyllary apex patent (vs. reflexed). It is also similar to S. ceterach Handel-Mazzetti (1938: 323) in its pinnately lobed leaves and nearly rosulate habit, but differs by its stems 10–16 cm tall (vs. 2–2.5 cm tall), capitula 1–5 on one stem (vs. solitary), phyllaries villous (vs. pubescent) and phyllary apex patent (vs. mostly appressed, outer ones reflexed). A comparison of S. zayuensis with its related species is given in Table 14.

Figures

FIGURE 17. Saussurea zayuensis. A. Habit. B. Outer pappus bristle. C. Inner pappus bristle. D. Anther. E. Style branches. F. Phyllaries (from left to right, outer to inner series). G. Floret.All from FLPH Tibet Expedition 12-1349 (PE). Drawn by Mrs. Z.J. Chen.