Saussurea khunjerabensis Y. S. Chen, 2022

Li, Tian, Xu, Lian-Sheng & Chen, You-Sheng, 2022, Saussurea khunjerabensis (Asteraceae, Cardueae), a new species from Pamir, Phytotaxa 561 (1), pp. 65-74 : 69-72

Saussurea khunjerabensis Y. S. Chen , sp. nov. ( Fig. 2 , 3 )

Type: — CHINA. Taxkorgan county , Khunjerab pass, alpine scree slopes, 5000 m, 22 July 2000, Ping Yan & Hui Sun 3527 (holotype: IBSC; isotypes: SHI, XJBI) .

Herbs perennial, 11–25 cm high, monocarpic. Caudex stout, unbranched. Stem solitary, ca. 2 cm in diameter, erect, simple, usually hidden by reflexed leaves, basally covered with fibrous remains of petioles; stem, cauline leaves and synflorescence covered with dense white or yellowish arachnoid lanate. Rosette and stem leaves petiolate; petioles 1–4 cm long; leaf blade linear or linear-oblong, 2–9 cm long, 3–8 mm wide, both surfaces light green, base attenuate; leaf blade margin 2–8 pinnately lobed or pinnatifid, lobe linear, 1–5 mm long, apex acute. Uppermost stem leaves linear, sessile, 1–3 cm long, 1–2 mm wide, usually reflexed, both surfaces densely white or yellowish arachnoid lanate, margin entire, apex acute. Capitula numerous, densely congested on the top of stem in a hemispheric synflorescence 5–10 cm in diameter, exposed at flowering time, sessile. Involucre cylindric, 5–8 mm in diameter. Phyllaries in 3–4 rows, membranous, apex acute; outer phyllaries linear-lanceolate, 15–20 mm long, ca. 3 mm wide, purple and densely white lanate; middle phyllaries triangular-lanceolate, 13–15 mm long, ca. 2 mm wide, purple and densely white lanate; inner phyllaries narrowly triangular-lanceolate, 10–13 mm long, ca. 1.5 mm wide, apically purple and densely white lanate. Receptacle bristles ca. 3 mm. Corolla purple, 10–15 mm long, tube ca. 7.5 mm long, limb ca. 8 mm long, lobes ca. 4 mm long. Achenes cylindroid, brown, obconic, 3–4 mm long, ribbed, glabrous. Pappus straw-colored; outer bristles 2–3 mm, scabrid; inner bristles 13–15 mm, plumose.

Phenology

Flowering and fruiting from late July to September.

Etymology

Saussurea khunjerabensis is named after its type locality, Khunjerab pass, Xinjiang, China.

Distribution and habitat

Saussurea khunjerabensis is currently only known from Khunjerab pass, Taxkorgan county, southwestern Xinjiang province, China, and adjacent Khunjerab pass area in Pakistan ( Fig. 5 ). It grows on alpine scree slopes at altitudes of 4500~ 5000 m.

Conservation status

Saussurea khunjerabensis is only found in the Khunjerab pass border area between China and Pakistan. This species is severely overcollected by local people as “snow lotus”. Many species of S. subg. Eriocoryne are included in the IUCN red list due to their small geographic ranges, few and severely fragmented populations, and in continuing decline due to excessive medicinal collection. According to the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Subcommittee 2019), the conservation status of this species should be assessed as Critically Endangered (CR, B2ab).

Similar species and phylogenetic position:

Saussurea khunjerabensis belongs to S. subgen. Eriocoryne because of its capitula being usually aggregated in a densely congested hemispheric synflorescence and hollow stems. In addition, the capitula is usually surrounded or half-surrounded by densely lanate subtending leaves. Saussurea khunjerabensis is similar to S. simpsoniana ( Fig. 5 ) in its habit, distinct elongate erect flowering stems, uppermost linear stem leaves reflexed, numerous aggregated capitula exposed on stem apex, straw-colored pappus and purple corolla, but different by its stems usually unbranched and 11–25 cm tall (vs. usually branched and 2–12 cm tall), rosette and stem leaves on both surfaces light green and densely white arachnoid lanate (vs. adaxially dark green or purplish, sparsely arachnoid; abaxially grayish white, arachnoid tomentose to lanate), rosette and stem leaf margins usually pinnately lobed or divided (vs. usually dentate to pinnately lobed, revolute), capitula in a hemispheric synflorescence 5–10 cm in diam. (vs. 2–3.5 cm in diam.), white or yellowish lanate indumentum (vs. white or purple lanate indumentum), phyllaries linear-lanceolate to narrowly triangular-lanceolate (vs. narrowly triangular-ovate or narrowly ovate-elliptic to linear), ribbed and glabrous achene ca. 3–4 mm long (vs. wrinkled achene ca. 2–3 mm long). According to Flora of China ( Shi & Raab-Straube 2011), S. simpsoniana is mainly distributed in Qinghai, southwestern Xinjiang, southern and southwestern Tibet. However, we found that the specimens of S. simpsoniana collected in Xinjiang are misidentified and actually belong to S. khunjerabensis . Chen (2015) considered that S. simpsoniana only occurs in Tibet of China, Nepal, India and Kashmir. Therefore, the geographical distributions of these two species are different in China and may overlap in Pakistan ( Fig. 5 ).

Saussurea khunjerabensis is also similar to S. gossipiphora ( Fig. 4 ) in its habit, size, distinct elongate erect and unbranched flowering stems, rosette and lower stem leaves petiolate, white or yellowish lanate indumentum and purple corolla, but distinguished by its rosette and stem leaves on both surfaces light green and densely white or yellowish arachnoid lanate (vs. both surfaces green and sparsely pilose or glabrous), lower leaf blade margins pinnately lobed or divided (vs. sparsely denticulate), capitula exposed on stem apex (vs. capitula surrounded and exceeded by densely lanate bracts), phyllaries linear-lanceolate to narrowly triangular-lanceolate (vs. ovate or narrowly ovate-elliptic to linear), achenes brown and ribbed (vs. black and smooth).

Morphological differences among Saussurea khunjerabensis , S. simpsoniana and S. gossipiphora are summarised in Table 2 .

Additional specimens examined (paratypes)

CHINA. Taxkorgan county, Khunjerab pass, 4800 m, 4 September 2013, Y. S. Chen 13-2280 (PE); Taxkorgan county, Khunjerab pass, 4700 m, August 1974, K. J. Feng 1 (HNWP); Taxkorgan county, Shuibulanggou, 4520 m, 15 July 1978, Xinjiang Exped. 1465 (PE). PAKISTAN. Khunjerab National Park, Khunjerab pass, 4800 m, 4 September 2013, Y. S. Chen 13-2279 (PE).

Figures

FIGURE 2. Living plants of Saussurea khunjerabensis. A–C. Habitat of S. khunjerabensis. All photos by Xu-Guang Yan from Khunjerab pass, Taxkorgan county, China.

FIGURE 3. Saussurea khunjerabensis. A. Habit; B. Style branches; C. Corolla; D.Achene with pappus; E. Inner pappus; F. Outer pappus; G. Anther; H. Phyllaries (from left to right: outer to inner). Drawn by Miss Shu-Han Li, based on the holotype.

FIGURE 4. Living plants of Saussurea simpsoniana. A. Lanate indumentum; B–C. Capitulum; D. Habitat; from Humla district, Nepal, S. R. Zhang, Y. S. Chen et al. H0866 (PE). All photos by You-Sheng Chen.

FIGURE 5. Distribution of Saussurea khunjerabensis (●).