Vincetoxicum hirundinaria subsp. hirundinaria

Vincetoxicum hirundinaria Medik., Hist. & Commentat. Acad. Elect. Sci. Theod.-Palat. 6:404. 1790 (Syn: Alexitoxicon albidum (Jord. & Fourr.) St.-Lag.; Alexitoxicon alpicola (Jord. & Fourr.) St.-Lag.; Alexitoxicon beugesiacum (Jord. & Fourr.) St.-Lag.; Alexitoxicon dumeticola (Jord. & Fourr.) St.-Lag.; Alexitoxicon laxum (Bartl.) St.-Lag.; Alexitoxicon ochroleucum (Jord. & Fourr.) St.-Lag.; Alexitoxicon petrophilum (Jord. & Fourr.) St.-Lag.; Alexitoxicon puberulum (Timb.-Lagr.) St.-Lag.; Alexitoxicon shuttleworthianum St.-Lag.; Antitoxicum laxum (Bartl.) Pobed.; Asclepias alba Mill.; Cynanchum kenouriense Wight; Cynanchum kenowiense K.Schum.; Cynanchum laxum Bartl.; Cynanchum vulgare Pers.; Otanema ovata Raf.; Vincetoxicum albidum Jord. & Fourr.; Vincetoxicum album Asch.; Vincetoxicum alpicola Jord. & Fourr.; Vincetoxicum beugesiacum Jord. & Fourr.; Vincetoxicum croaticum Jord. & Fourr.; Vincetoxicum daniloi (Rohlena) A.W.Hill; Vincetoxicum dumeticola Jord. & Fourr.; Vincetoxicum fradinii Pomel; Vincetoxicum hirundinaria var. balearicum O.Bolòs & Vigo; Vincetoxicum hirundinaria subsp. laxum (Bartl.) Poldini; Vincetoxicum hirundinaria f. puberulum (Beck) Sutorý; Vincetoxicum hirundinaria var. timbal-lagravei Sutorý; Vincetoxicum laxum (Bartl.) K.Koch; Vincetoxicum micranthum Shuttlew.; Vincetoxicum ochroleucum Jord. & Fourr.; Vincetoxicum petrophilum Jord. & Fourr.; Vincetoxicum pubens Timb.-Lagr.; Vincetoxicum puberulum Timb.-Lagr.; Vincetoxicum racemosum Timb.-Lagr.; Vincetoxicum ruscinonensis Timb.-Lagr.; Vincetoxicum stenolobum Shuttlew.; Vincetoxicum vulgare Bernh.) as per POWO;

Native to: Albania, Algeria, Austria, Baleares, Baltic States, Belarus, Belgium, Bulgaria, Central European Rus, Czechoslovakia, Denmark, East European Russia, East Himalaya, Finland, France, Germany, Greece, Hungary, Italy, Kazakhstan, Krym, Morocco, Nepal, Netherlands, Norway, Pakistan, Poland, Romania, South European Russi, Sweden, Switzerland, Turkey, Turkey-in-Europe, Ukraine, West Himalaya, West Siberia, Yugoslavia;
Introduced into: Michigan, New York, Ontario as per POWO;

As per efi thread:
I found it to be not V. hirundinaria as the description in Flowers of the Himalaya states: 'Corolla c. 5mm across, with nearly hairless triangular lobes' and 'calyx-lobes triangular, nearly as long as corolla' for V. hirundinria. 
The plants here have hair on the inside of corolla lobes and calyx is much shorter than the corolla. The description matches more closely to the Cynanchum glaucum in Flora Simlensis: 'Calyx about half as long as the corolla. Corolla hairy on the inner surface.'
Tibetan Medicinal Plant treats C. glaucum (V. glaucum) as a synonym of V. canescens and describes it as:
'Corolla yellow or green fading to greenish orange; tube approximately 1mm; lobes ovate, 2-3 x 1.5 mm, hairless outside, sparsely hirsute inside; sepals less than 1mm.'
SK 2636 26 June 2020 : 9 posts by 2 authors.
Location: Phulchoki, Lalitpur, Nepal
Date: 20 June  2020
Altitude: 2257 m.
Habitat : Wild
Vincetoxicum canescens (Willd.) Decne. or some susp.??

I think this should be Vincetoxicum hirundinaria Medik. of Checklist of Nepal as per keys in Flora of Pakistan as Corolla lobes glabrous within.
POWO and Flora of Pakistan give its distribution in Nepal.