Salix elongata L. He & Z.X. Zhang, 2014

Salix elongata L. He & Z.X. Zhang , sp. nov. ( Fig. 1 View FIGURE 1 )

Section assignment:— Sect. Floccosae K.S. Hao ex C.F. Fang & A.K. Skvortsov (1998: 470) .

Type:— China. Tibet (Xizang): Zayü County, Azha Glacier, 29°07′21.54′′N, 96°50′25.33′′E, 3644 m, 3 September 2012, L. He & S. Liao PH2012090302 (holotype BJFC! GoogleMaps , isotypes BJFC! GoogleMaps , PE! GoogleMaps ).

Dwarf shrubs, 0.1–0.2 m. Stems decumbent, rooting; branchlets supine or ascending, dull brown, dark yellow green when young, glabrous, shiny. Buds ovoid, ca. 5mm, glabrous. Petiole 1.5–5.1 cm, 0.6–1.1 times as long as blades, glabrous; leaf blade narrowly obovate or obovate, 1.6–5.6 × 1.2–2.2 cm, abaxially grayish white, pruinose, glabrous, proximal blade usually with white villous, adaxially dull green, base cuneate, margin remotely crenate, entire proximally, apex acute or obtuse. Male catkin unknown. Female catkin terminal on juvenile branchlets, 2.7–4.6 × 0.9–1.2 cm; moderately densely flowered; peduncle 2.5–8.6 cm, with 5 or 6 leaflets; rachis pubescent; bracts brown, oblong, narrowly obovate or obovate, apex rounded, 2.2–2.5 mm, glabous, or abaxially pubescent and sparsely ciliate. Female flower: adaxial nectary narrowly ovate, 0.5–1.1 mm, apex truncate, small abaxial nectary sometimes present, rectangular; ovary long ovoid, glabrous; stipe 0.8–1.3 mm, equal to or longer than adaxial nectary; styles distinct 1/2 their lengths, 0.6–0.8 mm; stigmas 2-lobed, 0.1 –0.24 mm. Capsule ca. 5mm.

Distribution:—Currently, Salix elongata is known only from Zayü, southeastern Tibet (Xizang), China ( Fig. 3 View FIGURE 3 ).

Habitat:—The species occurs at elevations between 3500 and 3900 m among low shrubs or in grassy meadows on rocky slopes, where it is dominant.

Etymology:—The specific epithet ‘ elongata ’ refers to the long petioles, which are usually as long as the leaf blades.

Paratypes:— China. Tibet (Xizang): Zayü County, Tsa-wa-rung, Hi-ma-la , 3500 m, August 1935, C. W. Wang 65636 ( PE! ♀) ; Zayü County, Tsa-wa-rung, Ree-su-la, Gerda , 3700 m, August 1935, C.W. Wang 65928 ( PE! ♂?, a male deciduous catkin on this specimen is annotated “♀”in the "flower" option of the collection record. We do not describe this male catkin because it may belong to another specimen) ; Zayü County, Azha, 3900 m, 12 August 1973, J.W. Zhang 1033 ( PE! ♀) ; Zayü County, Azha, 3600 m, 13 August 1973, Qinghai-Xizang Expedition 73- 1094 ( PE! ♀) .

Affinities:— Salix elongata is very similar to S. opsimantha C.K. Schneid. (1916: 63) , both having terminal catkins, oblong bracts, and glabrous ovaries. It is distinguished from S. opsimantha by its long petioles, ovary stipes equal to or longer than the adaxial nectary, up to 1.3 mm long, styles distinct over half of their lengths, stigmas 0.1–0.24 mm, plants 0.1–0.2 m tall, stems rooting ( Fig. 2E–H View FIGURE 2 ; Table 1 View TABLE 1 ).

Because of its dwarf habit (<0.2 m tall), terminal catkins, peduncle with leaflets, brown bracts, and distribution in only in the Pan-Himalayas, S. elongata is assigned to Sect. Floccosae K.S. Hao ex C.F. Fang & A.K. Skvortsov.