Vincetoxicum lenifolium S.A. Shah, 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

6. Vincetoxicum lenifolium S.A. Shah sp. nov. Figs 2Q, R, U, V , 3F , 4I, J, M , 6 , 13

Diagnosis.

Differing from V. stocksii by having broader (2.5-4.7 × 1-4.5 cm), ovate leaves with lamina glabrous to inconspicuously puberulent, green flowers, internally glabrous corolla lobes, and small, ca. 0.7 mm long, usually rhomboid corona lobes. In V. stocksii , leaves are narrowly ovate to narrowly or broadly lanceolate, rarely elliptic-ovate (3-6 × 1-2 cm) with lamina sparsely pubescent on both sides, flowers bicolored, corolla lobes pilose within, and corona lobes subulate and longer than the gynostegium (ca. 1 mm long).

Type.

Pakistan. Razmak [ North Waziristan ], 193[0s], N. Ali 1035 (Holotype: RAW) .

Undershrubs, ca. 50 cm tall. Stem striate, pubescent along one or two lines, rarely all around, internodes 2-7 cm long. Leaves opposite; petioles 4-15 mm long, pubescent all around or only along the adaxial channel; lamina discolorous, sometimes seemingly unifacial, lanceolate-ovate to ovate, 2.5-4.7 × 1-4.5 cm, spreading, sometimes pendent; apex acute to narrowly acute to shortly acuminate; base round or sub-cordate; veins prominent on both surfaces, secondary veins 8-10 (-14) on each side of midvein, both adaxial and abaxial surfaces mostly glabrous to inconspicuously puberulent, adaxial veins densely pubescent, abaxial veins and lamina margins glabrescent. Inflorescences long-pedunculate in the lower nodes to sessile in the upper nodes; peduncles up to 2.5 cm long, puberulent all around or along 1-2 lines; bracts linear, 2 mm long. Flowers green, ca. 3 × 2 mm; pedicels 2-5 mm long; sepals tapering to acute or narrowly acute apices, ca. 1.5 mm long, margins ciliate, abaxial surface sometimes pubescent, calycine colleters 10 per flower; corolla tube ca. 1 mm long, lobes oblong-ovate with obtuse or emarginate apex, 1.5-2.5 × 1-1.3 mm, glabrous within; corona lobes rhomboid, sometimes variable shapes found: conical-rhomboid, deltoid-rhomboid, rarely elongated, almost equal in length and width, 0.4-0.7 × 0.4-0.8 mm, reaching the base of the staminal appendages, erect to slightly divergent; staminal appendages obtuse. Follicles fusiform, 5-8 × 0.4-0.7 cm, apex acuminate, surface glabrous to glabrescent, striate. Seeds light brown, ca. 4 × 2.2 mm, wings less than 1 mm broad; coma up to 2 cm long.

Distribution and habitat.

Endemic to Khyber Pakhtunkhwa province of Pakistan. So far, it has been recorded from North & South Waziristan and Kohat districts. The elevation ranges from 1500 to 2000 m. Its habitat is open rocky slopes consisting of small stones and gravel and stream beds.

Etymology.

The name is based on smooth, mostly glabrous, leaves of the species.

Phenology.

Flowering from April to June and fruiting from July to August.

Provisional conservation status.

Endangered (Table 1 ). Vincetoxicum lenifolium is endemic to a small range comprising three districts of Khyber Pakhtunkhwa province, Pakistan. In 2016, we collected fresh specimens and observed its population structure in Razmak (North Waziristan). The population was clumped with less than 20 individuals. Anthropogenic activities like land degradation, settlements, roads etc. are deemed major threats to its existence.

Notes.

From the general appearance, V. lenifolium appears as a closely related member of the purple-flowered Vincetoxicum including V. arnottianum , V. luridum , V. sakesarense and V. stocksii . The paratypic specimens of this species were hitherto misidentified as V. arnottianum or V. hirundinaria . However, the new species is easily distinguished by ovate leaves, green flowers and glabrous corolla from V. arnottianum and by inconspicuous veins, denser inflorescences and small rhomboid corona from V. hirundinaria . RAW houses a variable specimen, N. Ali 1029, which is silvery in appearance, with sessile inflorescences and corona lobes somewhat deltoid (Fig. 3H ). These characters and the associated geographic information do not support the recognition of the specimen as a separate taxon. The specimen is cited as V. lenifolium in this treatment. Long-pedunculate inflorescences are most commonly found in V. lenifolium and rarely in V. stocksii . Short-pedunculate along with sessile inflorescences are found in V. arnottianum , V. cabulicum , V. cardiostephanum , rarely in V. kenouriense and V. sakesarense , V. luridum , V. stocksii , and V. subcanescens . Sessile inflorescences are found in V. glaucum and V. stewartianum .

Specimens examined.

Pakistan. Khyber Pakhtunkhwa: Kaniguram [South Waziristan], 13 May 1895, J.F. Duthie 15766 (RAW); Paryat (N. Waziristan), ± 5000 ft., 01 June 1979, M. Zubair & S. Khan 114964 & 114967 (ISL); Enger ( North Waziristan ), 21 June 1977, H. Ullah & Ayaz 56417 & 56418 (ISL); North Waziristan : Razmak, sandy slope on roadside near Razmak bazaar, 7545 ft., 08 September 2016, S.A. Shah SAS-44 (RAW US); Razmak, 29 May 1979, M. Zubair & Dilawar 112288 (ISL); Razmak, ± 6500 ft., 29 May 1979, M. Zubair & S. Khan 112298 (ISL); Razmak [North Waziristan], 193[0s], N. Ali 1029 (RAW!); Togh Sarai, Kohat [KPK], 31 March 1979, M. Zubair & S. Khan 113954 (ISL) .

Figures

Figure 2. Outlines of leaves of southern Asian Vincetoxicum. All illustrated specimens are housed at RAW. The first image in each pair corresponds to the adaxial surface and the second to the abaxial surface. All leaves have been taken from the middle of the stem A, B Vincetoxicum sp. aff. arnottianum from S. A. Shah SAS- 9 C, D Vincetoxicum sp. aff. arnottianum from S. A. Shah SAS- 46 E, F Vincetoxicum sp. aff. arnottianum from R. Khan SAS- 41 G, H V. arnottianum from S. A. Shah & F. Rahman SAS- 3 I, J V. arnottianum from S. A. Shah & B. Ali SAS- 4 K, L V. cabulicum from D. Podlech 15814 M, N V. cardiostephanum from S. A. Shah, M. Turi et al. SAS- 40 O, P V. kenouriense from S. A. Shah & L. Ahmad SAS- 37 Q, R V. lenifolium from S. A. Shah SAS- 44 S, T V. luridum from S. A. Shah & I. Ahmad SAS- 23 U, V V. lenifolium from N. Ali 1029 W, X V. sakesarense from I. Ahmad 27821 Y, Z V. stewartianum from R. R. Stewart 16709 AA, AB V. stocksii from B. Gul, N. Khan et al. SAS- 21 AC, AD V. subcanescens from A. Sultan, Z. Saqib et al. SAS- 52 AE, AF V. subcanescens from S. A. Shah & A. Ullah SAS- 8. Drawing by M. Saleem and S. A. Shah.

Figure 3. Illustration of corona types observed in southern Asian Vincetoxicum. The dark coloured shapes show corona lobes A Vincetoxicum arnottianum from S. A. Shah & B. Ali SAS- 4 (RAW) B V. cabulicum from W. Koelz 11764 (US) C V. cardiostephanum from S. A. Shah, M. Turi et al. SAS- 40 (RAW) D V. glaucum from W. Dudeeon & L. A. Kenoyer 56 (MO) E V. kenouriense from S. A. Shah & L. Ahmad SAS- 37 (RAW) F V. lenifolium from S. A. Shah SAS- 44 (RAW) G V. luridum from S. A. Shah & I. Ahmad SAS- 23 (RAW) H A variable specimen of V. lenifolium from N. Ali 1029 (RAW) I V. sakesarense from I. Ahmad 27821 (RAW) J V. stewartianum from R. R. Stewart 16709 (RAW) K V. stocksii from J. F. Duthie 18918 (RAW) L V. subcanescens from S. A. Shah & A. Ullah SAS- 8 (RAW). Drawing by M. Saleem and S. A. Shah.

Figure 4. Pollinaria of southern Asian Vincetoxicum A, B V. arnottianum C V. cabulicum D, E V. cardiostephanum F V. glaucum G, H V. kenouriense I, J V. lenifolium K, L V. luridum M V. lenifolium N, O V. sakesarense P V. stewartianum Q, R V. stocksii S, T V. subcanescens.

Figure 6. Geographic distribution of southern Asian Vincetoxicum. The colour of the symbols corresponds to the colour of the corolla.

Figure 13. Vincetoxicum lenifolium illustrated by S. A. Shah & S. U. Nisa from N. Ali 1035 (RAW) A plant with fruits and flowers B flower, top view.