Saussurea pseudotridactyla 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 : 162-164

2. Saussurea pseudotridactyla Y. S. Chen , sp. nov. ( Fig. 2 )

Type:— CHINA. Xizang: Cona County, Langpo Xiang , Dongzhang waterfall to Xiaozhan , 27°46 ʹ N, 91°58 ʹ E, alpine periglacial scree zone, 3700 m, 11 August 2013, FLPH Tibet Expedition 13-0926 (holotype PE; isotypes PE) .

Herbs perennial, 5–12 cm tall, polycarpic, usually forming a large clump. Caudex stout, branched at ground level, with several to numerous sterile leaf rosettes and flowering stems. Stems usually several, ca. 4 mm in diameter, erect, simple, hidden by reflexed leaves. Sterile leaves rosulate, spathulate, 1–3 cm long, 3–7 mm wide, adaxially green to grayish white, sparsely white arachnoid, abaxially grayish white, densely white arachnoid tomentose, margin obscurely few-dentate, apex obtuse. Rosette and lower flowering stem leaves shortly petiolate; leaf blade spathulate, (1–) 2–3.5 cm long, 4–7 mm wide, both surfaces densely white arachnoid, base cuneate-attenuate, margin obscurely few-dentate to nearly entire, apex obtuse. Upper flowering stem leaves linear, purplish red, 10–30 mm long, 1–2.5 mm wide, usually reflexed, both surfaces densely white and dark brown lanate, margin entire or obscurely few dentate, apex acute. Capitula numerous, in a hemispheric synflorescence 2.5–3.5 cm in diameter, sessile, exposed at anthesis. Involucre cylindroid, 4–6 mm in diameter. Phyllaries in 3–4 rows, membranous, apex acute; outer phyllaries narrowly triangular-ovate, 11–13 mm long, 2.5–3 mm wide, densely brown villous; inner phyllaries narrowly elliptic to linear, 9–10 mm long, 1–2 mm wide, apically purple and sparsely brown villous. Receptacle bristles ca. 0.5 mm long. Corolla purple, 9–9.5 mm long, tube 4–4.5 mm long, limb ca. 5 mm long, lobes ca. 2.5 mm long, linear. Anthers purplish black, 4–5 mm long, auricles with white lanate tails 0.5–1 mm long. Achenes cylindroid, brown, 3.8–4 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 7–10 mm long, long plumose.

Distribution and habitat:— Saussurea pseudotridactyla is currently known only from Cona County, southern Xizang, China. It grows on alpine periglacial scree zone or alpine meadows at altitudes of 3700–4530 m.

Phenology:—Flowering and fruiting from August to September.

Etymology:—The specific epithet reflects the similarity of the new species to S. tridactyla Schultz Bipontinus ex Hooker (1881: 377) . Chinese name: LJΞffiǞÊT.

Additional specimens examined (paratypes):— CHINA. Xizang: Cona County, Bai Shan Pass, 27°55 ʹ N, 91°52 ʹ E, alpine scree or meadows, 4530 m, 12 August 2013, FLPH Tibet Expedition 13-0994 (PE).

Discussion:—In our molecular tree, S. pseudotridactyla is shown to be very close to S. tridactyla Schultz Bipontinus ex Hooker (1881: 377) . It is similar to S. tridactyla in its polycarpic habit, stem hidden by reflexed leaves, rosette and lower stem leaves densely white arachnoid on both surfaces, synflorescence hemispheric and exposed at anthesis, and outer bristles 2–4 mm long, plumose, but differs by the plant usually forming a large clump (vs. never forming a large clump and nearly monocarpic), its sterile and lower flowering stem leaves obscurely few-dentate to nearly entire at margin (vs. apically 3–6-toothed), lower flowering stem leaves densely white arachnoid on both surfaces, upper flowering stem leaves purplish red and densely white and dark brown lanate on both surfaces (vs. all leaves similar in color, both surfaces densely white or yellowish lanate), and pappus dark brown (vs. straw-clored to light brown). A comparison of S. pseudotridactyla with related taxa is given in Table 2.

Figures

FIGURE 2. Saussurea pseudotridactyla. A. Habit. B. Style branches. C. Achene. D. Anther. E. Inner pappus bristle. F. Outer pappus bristle. G. Floret. H. Floret (with pappus removed). I. Phyllaries (from left to right, outer to inner series). All from FLPH Tibet Expedition 13-0926 (PE). Drawn by Mrs. Z.J. Chen.