Saussurea pseudoleucoma 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 : 164-166

3. Saussurea pseudoleucoma Y. S. Chen , sp. nov. ( Fig. 3 )

Type:— CHINA. Xizang: Lhünzê County, Yumen Xiang , Rila Shan pass, 28°41 ʹ N, 93°2 ʹ E, alpine scree, 4600–4800 m, 5 August 2013, FLPH Tibet Expedition 13-0368 (holotype PE; isotypes PE) .

Herbs perennial, 5–13 cm tall, polycarpic. Caudex stout, usually abundantly and long branched at underground level, with numerous sterile leaf rosettes and flowering stems. Flowering stems usually 3–5 mm in diameter, erect, simple, densely white arachnoid tomentose, hidden by reflexed leaves. Sterile leaves rosulate, petiolate; petioles 5–25 mm long, white arachnoid tomentose; leaf blade ovate, 1.5–3 cm long, 5–18 mm wide, adaxially grayish white, densely white arachnoid tomentose, abaxially grayish white, densely white arachnoid tomentose, margin pinnately lobed (lobes 3–4 pairs) to coarsely dentate, apex obtuse. Lower and middle flowering stem leaves shortly petiolate; leaf blade lanceolate, usually purplish red, 3–4.5 cm long, 5–8 mm wide, both surfaces densely white or light brown arachnoid tomentose, base cuneate-attenuate, margin pinnately lobed to dentate, apex acute. Uppermost flowering stem leaves sessile; leaf blade usually purplish red, linear-lanceolate, much smaller than lower leaves, both surfaces densely white or light brown arachnoid tomentose, margin toothed to entire, apex acuminate. Capitula numerous, in a hemispheric synflorescence 3–5.5 cm in diameter, sessile, exposed at anthesis. Involucre cylindroid, 4–6 mm in diameter. Phyllaries in 3–4 rows, membranous, apex obtuse and sparsely villous; outer phyllaries oblong to elliptic, ca. 15 mm long, ca. 4 mm wide, glabrous, apex obtuse and sparsely villous; inner phyllaries oblong to elliptic, 16–17 mm long, 2.5–3.8 mm wide, apically purple and ciliate to glabrous. Receptacle naked. Corolla purple, ca. 14.5 mm long, tube ca. 9 mm long, limb ca. 5.5 mm long, lobes ca. 2.5 mm long, linear. Anthers purplish black, ca. 6 mm long, auricles with white lanate tails ca. 1.5 mm long. Achenes cylindroid, brown, ca. 3 mm long, ribbed, glabrous, apex with a short truncate crown. Pappus dark brownish; outer bristles 4–5 mm long, plumose, caducous, slender than inner bristles; inner bristles ca. 15 mm long, long plumose.

Distribution and habitat:— Saussurea pseudoleucoma is currently known only from Lhünzê County, southern Xizang, China. It grows on alpine periglacial scree zone at altitudes of 4600–4800 m.

Phenology:—Flowering and fruiting from August to September.

Etymology:—The specific epithet is derived from the name of its similar species, S. leucoma Diels (1912: 197) . Chinese name: LJflṄǞÊT.

Discussion:—In our molecular tree, S. pseudoleucoma is shown to be close to S. tridactyla and S. pseudotridactyla . It is similar to S. tridactyla and S. pseudotridactyla in its polycarpic habit, synflorescence exposed at anthesis, leaves densely white arachnoid tomentose, and outer pappus plumose, but distinct by its sterile leaves ovate, flowering stem leaves lanceolate to linear, leaves pinnately lobed (lobes 3–4 pairs) to coarsely dentate, phyllaries apex obtuse, receptacle naked, and inner pappus ca. 15 mm long. It is also similar to S. leucoma in its polycarpic habit, synflorescence exposed at anthesis, leaves densely white arachnoid tomentose, and leaf blade pinnately lobed, but differs by its sterile leaves ovate and grayish white, flowering stem leaves lanceolate to linear, purplish red (vs. all leaves narrowly elliptic, light green), phyllary apex obtuse (vs. acuminate), receptacle naked (vs. bristles 1–3 mm long), pappus dark brown (vs. straw-colored), and outer pappus plumose (vs. scabrid). Saussurea pseudoleucoma is somewhat similar to S. quercifolia Smith (1913: 115) in its polycarpic habit, synflorescence exposed at anthesis, leaves densely white arachnoid tomentose, and leaf blade pinnately lobed to dentate, but differs by its sterile leaves ovate, flowering stem leaves lanceolate to linear, purplish red (vs. all leaves elliptic to narrowly elliptic, or lanceolate, light green), phyllary apex obtuse (vs. acute), receptacle naked (vs. bristly), pappus dark brown (vs. blackish), and outer pappus plumose (vs. scabrid). A comparison of S. pseudoleucoma with related taxa is given in Table 2.

Figures

FIGURE 3. Saussurea pseudoleucoma. A. Habit. B.Anthers. C. Style branches. D. Cross section of sessile leaves. E. Outermost phyllary. F. Cross section of outermost phyllary. G. Phyllaries (from left to right, outer to inner series). H. Outer pappus bristle. I. Inner pappus bristle. J. Florets (with pappus removed). K. Floret.All from FLPH Tibet Expedition13-0368 (PE). Drawn by Mr. Y.X. Zhu.