Vincetoxicum subcanescens S.A. Shah & A. Sultan, 2021

Shah, Sayed Afzal, Sultan, Amir, Wen, Jun, Ullah, Zahid, Nisa, Surat Un, Ren, Zhumei, Alam, Muhammad Maqsood, Iqbal, Javed & Mumtaz, Abdul Samad, 2021, Taxonomy of Vincetoxicum s. str. (Asclepiadoideae, Apocynaceae) from southern Asia including three new species and resurrected names, PhytoKeys 179, pp. 35-73 : 35

11. Vincetoxicum subcanescens S.A. Shah & A. Sultan sp. nov.

Diagnosis.

Differing from V. cabulicum by having distinctly petiolate leaves, green flowers, and clavate corona lobes. In V. cabulicum , leaves are sessile, flowers dark purple, and corona lobes obovate.

Type.

Pakistan. Dir Upper , Patraak, mountain slope near river, 1600 m, 16 June 2015, S.A. Shah & A. Ullah SAS-8A (Holotype: RAW!) .

Undershrubs, up to 75 cm tall. Stem and other vegetative parts sub-canescent, internodes 1-9 cm long, striate. Leaves opposite, rarely whorled on some nodes; petioles 1-18 mm long; lamina discolorous, narrow to broadly ovate to sometimes lanceolate-ovate, 3-9 × 1.2-4.8 cm; apex acute to narrowly acute to shortly acuminate; base rounded to sub-cordate to sub-truncate; veins visible on both sides, more prominent on adaxial side, secondary veins 6-12 on each side of midvein, tertiary veins sometimes visible, lamina sub-canescent on both sides. Inflorescences sessile or both sessile and pedunculate inflorescences present on the same plant; peduncles up to 2.5 cm long, sub-canescent; bracts narrow with a few marginal trichomes; pedicels 2-7 mm long, pubescent. Flowers green to yellowish-green, 3-4 × 2-2.5 mm; sepals tapering into acute to narrowly acute apices, pubescent along margins and abaxial surface, up to 2 mm long, calycine colleters single or in pairs; corolla tube ca. 1 mm long, lobes tapering into obtuse apex, 2-2.5 × 1-1.5 mm, margins appearing wavy in dry flowers, sub-bearded within; corona lobes clavate, 0.5-1 × 0.2-0.5 mm, reaching the base, the middle or, rarely, the apex of the staminal appendages, divergent. Follicles fusiform, 4.5-9.5 × 0.7-1 cm, sparsely pubescent, minutely striate, apex narrowly acuminate. Seeds 5-6 × 2-3 mm, wings up to 1 mm broad; coma up to 3 mm long.

Distribution and habitat.

Endemic to Pakistan (Chitral, Dir, Swat and Gilgit Baltistan), Kashmir (Ladakh) and China (Tibet). The habitat of the species is open slopes. Soil type is clay to gravel to large size stones. The elevation ranges from 1600 to 2800 m.

Etymology.

The name is based on the sub-canescent indumentum on the vegetative parts of the plant.

Phenology.

Vincetoxicum subcanescens flowers from April to August and fruits from May to October.

Provisional conservation status.

Least concern (Table 1 ). Vincetoxicum subcanescens is common in its range. However, the populations are extremely distant and clumped.

Vernacular name.

Lovaki (in Chitrali language).

Notes.

Vincetoxicum subcanescens was previously misidentified as V. canescens ( Ali and Khatoon 1982; Boissier 1879). Rechinger (1970) treated it as V. glaucum in Flora Iranica and also synonymized V. cabulicum with it. Vincetoxicum subcanescens differs from V. canescens by the subcanescent indumentum, smaller flowers, clavate corona lobes, and glabrous and narrowly fusiform follicles. Vincetoxicum canescens is distributed in the eastern Mediterranean region in Turkey, Greece, Syria and Iraq. It is characterized by canescent indumentum, larger flowers, arrow-shaped corona lobes, and ovate and canescent follicles. Vincetoxicum glaucum exhibits variable leaf shapes, sub-glabrous or glabrous leaf surfaces, sessile inflorescences and toothed corona lobes. It is distributed in the Himalayas of India and Nepal. The closest relative of V. subcanescens is V. cabulicum which differs by the sub-sessile leaves and dark purple corolla and is endemic to northern Afghanistan.

Specimens examined.

China. Tibet: Hab. Tibet, 10,000-12,000 ft., s.d., J. J. s. n. (GOET [GOET020098; GOET020099]) .

Kashmir. Nurla, Ladak, Kashmir. On sandy slope, 28 August 1931, W. Koelz 2707 (RAW, US) ; North of Kamri Pass , above Shankargarh, ca. 10,000 ft., s.d., R.R. Stewart 22773 (K, US) ; Kargil, Ladakh, Kashmir, 27-28 July 1933, W. Koelz 6132 ( US) .

Pakistan. Khyber Pakhtunkhwa: Chitral, Rosh Gol Tirich Mulkhow, 9039 ft., dry hard soil, 08 October 2013, Kifayat 516 (HUP); Chitral to Pirpesh, 8 June 1958, I.I. Choudhri 7 (RAW); Dir [Upper]: Patraak, 13 July 1968, Y. Nasir 5089 (RAW); Swat: Batain above Ushu cliffs, 27 July 1953, R.R. Stewart & A. Rehman 25301 (RAW); Gilgit Baltistan: Satpura Nullah near Skardu, s.d., A. Ghafoor 567 (KUH); Near Rattu above Astor, 21 August 1939, R.R & I.D. Stewart 18834 (RAW); Bagocha to Olding, Indus valley, ca. 8500 ft., 22 August 1940, R.R. Stewart 21009 (RAW); Indus Valley: below Parkutta, 20 August 1940, R.R. Stewart 20908 (RAW); Between Arkote and Biafo base camp, 3200 m, 05 June 1962, Schussalide 1095 (KUH); Astor: ± 30 km from Pagru on way to Shimshol, ± 3000 m, 25 June 2007, J. Alam et al. 3941 (KUH); Astor: Gorikot P.R.C, 26 May 2008, A. Noor & Basharat 1489 (KUH); Astor: Peer rant village, bank of cultivated field, 12 September 2004, A. Noor 52 (KUH); Astor: above Rattu, 2642 m, 23 August 2014, A. Sultan SAS-52 (RAW); Hunza, Gilgit, ± 35 km from Posu on way to Shimshol, 28 June 2007, J. Alam, Karimuddin & M. Khan 3941 (KUH); Dharkot, 10,500 ft., 19 June 1976, B. Lyon 8144 (KUH); Skardo-Dras, 8800 ft., petals green, acute, s.d., C.B. Clarke 30512A (K); B-9 Baltistan, Paskyum, 9600 ft., flowers greenish, s.d., B.B. Osmaston 129 (K); Gilgit: Chamrot, 29 July 1957, M.B. Zaman & D.K. D 1876 (PFI); Gilgit: Passu between lake and glacier, 16 August 1994, S.Z. Hussain, R.A.W. Lowe, M. Shah & L.S. Springate 632 (PMNH).