Cynanchum is a genus of about 300 species including some swallowworts, belonging to the family Apocynaceae. The taxon name comes from Greek kynos (meaning "dog") and anchein ("to choke"), hence the common name for several species is dog-strangling vine. Most species are non-succulent climbers or twiners. There is some evidence of toxicity.

Morphology

These plants are perennial herbs or subshrubs, often growing from rhizomes. The leaves are usually oppositely arranged and sometimes are borne on petioles. The inflorescences and flowers come in a variety of shapes.

Like other species of the milkweed family, these plants bear follicles, which are podlike dry fruits.

Distribution

These species are found throughout the tropics and subtropics. Several species also grow in temperate regions.

Importance

Species of the Cynanchum genus had traditional Chinese medicinal uses. The root of Cynanchum atratum is used in Chinese traditional medicine and called Bai wei (白薇). Baishouwubenzophenone is used in Cynanchum wilfordii, Cynanchum auriculatum (now Vincetoxicum auriculatum), and Cynanchum bungei.

Classification

Cynanchum as defined in the late 20th century (to include about 400 species) is polyphyletic and is being broken up. Species are being moved to genera including Orthosia, Pentarrhinum, and Vincetoxicum, with a group of mostly Old World species staying in Cynanchum, and old genera such as Raphistemma brought to synonymy. Revision of the genus taxonomy in 2023 identified two new synonyms: Vincetoxicum sibiricum f. linearifolium, described from Shandong, China in 1877, but long neglected and Cynanchum gobicum, previously believed to be endemic to Mongolia.

Species

, Plants of the World Online accepted the following species:

  • Cynanchum absconditum <small>Liede</small>
  • Cynanchum abyssinicum <small>Decne.</small>
  • Cynanchum acidum <small>(Roxb.) Oken</small>
  • Cynanchum aculeatum <small>(Desc.) Liede & Meve</small>
  • Cynanchum acuminatum <small>Humb. & Bonpl. ex Schult.</small>
  • Cynanchum acutum <small>L.</small>
  • Cynanchum adalinae <small>(K.Schum.) K.Schum.</small>
  • Cynanchum africanum <small>(L.) Hoffmanns.</small>
  • Cynanchum alatum <small>Wight & Arn.</small>
  • Cynanchum alternilobum <small>(M.G.Gilbert & P.T.Li) Liede & Khanum</small>
  • Cynanchum altiscandens<small> K.Schum.</small>
  • Cynanchum ambovombense <small>(Liede) Liede & Meve</small>
  • Cynanchum ampanihense <small>Jum. & H.Perrier</small>
  • Cynanchum analamazaotrense <small>Choux</small>
  • Cynanchum anderssonii <small>Morillo</small>
  • Cynanchum andringitrense <small>Choux</small>
  • Cynanchum angavokeliense <small>Choux</small>
  • Cynanchum annularium <small>(Roxb.) Liede & Khanum</small>
  • Cynanchum ansamalense <small>Liede</small>
  • Cynanchum anthonyanum <small>Hand.-Mazz.</small>
  • Cynanchum antsiranense <small>(Meve & Liede) Liede & Meve</small>
  • Cynanchum appendiculatopsis <small>Liede</small>
  • Cynanchum appendiculatum <small>Choux</small>
  • Cynanchum arabicum <small>(Bruyns & P.I.Forst.) Meve & Liede</small>
  • Cynanchum arenarium <small>Jum. & H.Perrier</small>
  • Cynanchum areysianum <small>(Bruyns) Meve & Liede</small>
  • Cynanchum balense <small>Liede</small>
  • Cynanchum baronii <small>Choux</small>
  • Cynanchum batangense <small>P.T.Li</small>
  • Cynanchum beatricis <small>Morillo</small>
  • Cynanchum bernardii <small>Morillo</small>
  • Cynanchum bicampanulatum <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum bisinuatum <small>Jum. & H.Perrier</small>
  • Cynanchum blandum <small>(Decne.) Sundell</small>
  • Cynanchum blyttioides <small>Liede</small>
  • Cynanchum bojerianum <small>(Decne.) Choux</small>
  • Cynanchum bosseri <small>Liede</small>
  • Cynanchum boudieri <small>H.Lév. & Vaniot</small>
  • Cynanchum boveanum <small>Decne.</small>
  • Cynanchum bowmanii <small>S.T.Blake</small>
  • Cynanchum brasiliense <small>(Morillo) Liede</small>
  • Cynanchum brevicoronatum <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum brevipedicellatum <small>(P.I.Forst.) Liede & Meve</small>
  • Cynanchum brevipedunculatum <small>J.Y.Shen</small>
  • Cynanchum bricenoi <small>Morillo</small>
  • Cynanchum bungei <small>Decne.</small>
  • Cynanchum callialatum <small>Buch.-Ham. ex Wight</small>
  • Cynanchum carautanum <small>(Fontella & E.A.Schwarz) Morillo</small>
  • Cynanchum caudiculatum <small>Rapini</small>
  • Cynanchum caudigerum <small>R.W.Holm</small>
  • Cynanchum celebicum <small>Schltr.</small>
  • Cynanchum chanchanense <small>Morillo</small>
  • Cynanchum chinense <small>R.Br.</small>
  • Cynanchum chouxii <small>Liede & Meve</small>
  • Cynanchum comorense <small>Choux</small>
  • Cynanchum compactum <small>Choux</small>
  • Cynanchum corymbosum <small>Wight</small>
  • Cynanchum crassiantherae <small>Liede</small>
  • Cynanchum crassipedicellatum <small>Meve & Liede</small>
  • Cynanchum cristalinense <small>Morillo</small>
  • Cynanchum cuatrecasasii <small>Morillo</small>
  • Cynanchum cubense <small>(A.Rich.) Woodson</small>
  • Cynanchum cucullatum <small>N.E.Br.</small>
  • Cynanchum cyathiforme (Sundell) <small>W.D.Stevens</small>
  • Cynanchum dalhousiae <small>Wight</small>
  • Cynanchum daltonii <small>(Decne.) Liede & Meve</small>
  • Cynanchum danguyanum <small>Choux</small>
  • Cynanchum decaryi <small>Choux</small>
  • Cynanchum decipiens <small>C.K.Schneid.</small>
  • Cynanchum decorsei <small>(Costantin & Gallaud) Liede & Meve</small>
  • Cynanchum defilippii <small>Delponte</small>
  • Cynanchum descoingsii <small>Rauh</small>
  • Cynanchum diazmirandae <small>Morillo</small>
  • Cynanchum dimidiatum <small>(Hassk.) Boerl.</small>
  • Cynanchum doleriticum <small>Goyder</small>
  • Cynanchum dombeyanum <small>(Decne.) Morillo</small>
  • Cynanchum duclouxii <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum elachistemmoides <small>(Liede & Meve) Liede & Meve</small>
  • Cynanchum elegans <small>(Benth.) Domin</small>
  • Cynanchum ellipticum <small>(Harv.) R.A.Dyer</small>
  • Cynanchum erikseniae <small>Morillo</small>
  • Cynanchum erythranthum <small>Jum. & H.Perrier</small>
  • Cynanchum ethiopicum <small>Liede & Khanum</small>
  • Cynanchum eurychitoides <small>(K.Schum.) K.Schum.</small>
  • Cynanchum eurychiton <small>(Decne.) K.Schum.</small>
  • Cynanchum falcatum <small>Hutch. & E.A.Bruce</small>
  • Cynanchum fasciculiflorum <small>Morillo</small>
  • Cynanchum fernandezii <small>Morillo</small>
  • Cynanchum fimbricoronum <small>P.T.Li</small>
  • Cynanchum floribundum <small>R.Br.</small>
  • Cynanchum floriferum <small>Liede & Meve</small>
  • Cynanchum foetidum <small>(Cav.) Kunth</small>
  • Cynanchum folotsioides <small>Liede & Meve</small>
  • Cynanchum forskaolianum <small>Meve & Liede</small>
  • Cynanchum fragrans <small>(Wall.) Liede & Khanum</small>
  • Cynanchum gentryi <small>(Morillo) Liede</small>
  • Cynanchum gerrardii <small>(Harv.) Liede</small>
  • Cynanchum gilbertii <small>Liede</small>
  • Cynanchum giraldii <small>Schltr.</small>
  • Cynanchum glomeratum <small>Bosser</small>
  • Cynanchum gobicum <small>Grubov</small>
  • Cynanchum goertsianum <small>Morillo</small>
  • Cynanchum gonoloboides <small>Schltr.</small>
  • Cynanchum gracillimum <small>Wall. ex Wight</small>
  • Cynanchum graminiforme <small>Liede</small>
  • Cynanchum grandidieri <small>Liede & Meve</small>
  • Cynanchum graphistemmatoides <small>Liede & Khanum</small>
  • Cynanchum guatemalense <small>Dugand</small>
  • Cynanchum guehoi <small>Bosser</small>
  • Cynanchum hardyi <small>Liede & Meve</small>
  • Cynanchum hastifolium <small>K.Schum.</small>
  • Cynanchum haughtii <small>Woodson</small>
  • Cynanchum hemsleyanum <small>(Oliv.) Liede & Khanum</small>
  • Cynanchum heteromorphum <small>Vatke</small>
  • Cynanchum heydei <small>Hook.f.</small>
  • Cynanchum hickenii <small>Malme</small>
  • Cynanchum hoedimeerium <small>Bakh.f.</small>
  • Cynanchum hooperianum <small>(Blume) Liede & Khanum</small>
  • Cynanchum hubeiense <small>Wen B.Xu, B.S.Xia & J.Y.Shen</small>
  • Cynanchum humbert-capuronii <small>Liede & Meve</small>
  • Cynanchum implicatum <small>(Jum. & H.Perrier) Jum. & H.Perrier</small>
  • Cynanchum insigne <small>(N.E.Br.) Liede & Meve</small>
  • Cynanchum insipidum <small>(E.Mey.) Liede & Khanum</small>
  • Cynanchum insulanum<small>(Hance) Hemsl.</small>
  • Cynanchum itremense <small>Liede</small>
  • Cynanchum jaliscanum <small>(Vail) Woodson</small>
  • Cynanchum jaramilloi <small>Morillo</small>
  • Cynanchum juliani-marnieri <small>Desc.</small>
  • Cynanchum jumellei <small>Choux</small>
  • Cynanchum junciforme <small>(Decne.) Liede</small>
  • Cynanchum kaschgaricum <small>Y.X.Liou</small>
  • Cynanchum kingdonwardii <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum kintungense <small>Tsiang</small>
  • Cynanchum kwangsiense <small>Tsiang & H.D.Zhang</small>
  • Cynanchum laeve - honeyvine
  • Cynanchum lanhsuense <small>T.Yamaz.</small>
  • Cynanchum lecomtei <small>Choux</small>
  • Cynanchum ledermannii <small>Schltr.</small>
  • Cynanchum leptolepis <small>(Benth.) Domin</small>
  • Cynanchum leptostephanum <small>Diels</small>
  • Cynanchum leucophellum <small>Diels</small>
  • Cynanchum ligulatum <small>(Benth.) Woodson</small>
  • Cynanchum lineare <small>N.E.Br.</small>
  • Cynanchum liukiuense <small>Warb.</small>
  • Cynanchum loheri <small>Schltr.</small>
  • Cynanchum longipedunculatum <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum longipes <small>N.E.Br.</small>
  • Cynanchum longirostrum <small>(K.Schum.) W.D.Stevens</small>
  • Cynanchum lopezpalaciosii <small>Morillo</small>
  • Cynanchum luteifluens <small>(Jum. & H.Perrier) Desc.</small>
  • Cynanchum lysimachioides <small>Y.Tsiang & P.T.Li</small>
  • Cynanchum maasii <small>Morillo</small>
  • Cynanchum macranthum <small>Jum. & H.Perrier</small>
  • Cynanchum macrolobum <small>Jum. & H.Perrier</small>
  • Cynanchum madagascariense <small>K.Schum.</small>
  • Cynanchum magale <small>Buch.-Ham. ex Dillwyn</small>
  • Cynanchum mahafalense <small>Jum. & H.Perrier</small>
  • Cynanchum malampayae <small>(Kloppenb., Cajano & Hadsall) Sodusta</small>
  • Cynanchum mariense <small>(Meve & Liede) Liede & Meve</small>
  • Cynanchum mariquitense <small>Mutis</small>
  • Cynanchum marnieranum <small>Rauh</small>
  • Cynanchum masoalense <small>Choux</small>
  • Cynanchum maximoviczii <small>Pobed.</small>
  • Cynanchum megalanthum <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum membranaceum <small>(Liede & Meve) Liede & Meve</small>
  • Cynanchum menarandrense <small>Jum. & H.Perrier</small>
  • Cynanchum messeri <small>(Buchenau) Jum. & H.Perrier</small>
  • Cynanchum mevei <small>Liede</small>
  • Cynanchum meyeri <small>(Decne.) Schltr.</small>
  • Cynanchum microstemma <small>(Turcz.) Morillo</small>
  • Cynanchum minahassae <small>Schltr.</small>
  • Cynanchum montevidense Spreng.
  • Cynanchum moramangense <small>Choux</small>
  • Cynanchum moratii <small>Liede</small>
  • Cynanchum mossambicense <small>K.Schum.</small>
  • Cynanchum muricatum <small>(Blume) Boerl.</small>
  • Cynanchum napiferum <small>Choux</small>
  • Cynanchum natalitium <small>Schltr.</small>
  • Cynanchum nematostemma <small>Liede</small>
  • Cynanchum nielsenii <small>Morillo</small>
  • Cynanchum obovatum <small>(Decne.) Choux</small>
  • Cynanchum obtusifolium L.f.
  • Cynanchum officinale <small>(Hemsl.) Tsiang & H.D.Zhang</small>
  • Cynanchum orangeanum <small>(Schltr.) N.E.Br.</small>
  • Cynanchum oresbium <small>(Bruyns) Goyder</small>
  • Cynanchum otophyllum <small>C.K.Schneid.</small>
  • Cynanchum ovalifolium <small>Wight</small>
  • Cynanchum pachycladon <small>Choux</small>
  • Cynanchum pamirense <small>Tsiang & H.D.Zhang</small>
  • Cynanchum papillatum <small>Choux</small>
  • Cynanchum paramorum <small>Morillo</small>
  • Cynanchum pearsonianum <small>Liede & Meve</small>
  • Cynanchum pedunculatum <small>R.Br.</small>
  • Cynanchum peraffine <small>Woodson</small>
  • Cynanchum perrieri <small>Choux</small>
  • Cynanchum petignatii <small>Liede & Rauh</small>
  • Cynanchum phillipsonianum <small>Liede & Meve</small>
  • Cynanchum physocarpum <small>Schltr.</small>
  • Cynanchum pichi-sermollianum <small>(Raimondo & Fici) Liede & Khanum</small>
  • Cynanchum pietrangelii <small>Morillo</small>
  • Cynanchum polyanthum <small>K.Schum.</small>
  • Cynanchum praecox <small>Schltr. ex S.Moore</small>
  • Cynanchum prevostii <small>Morillo</small>
  • Cynanchum puberulum <small>F.Muell. ex Benth.</small>
  • Cynanchum pulchellum <small>(Wall.) Liede & Khanum</small>
  • Cynanchum purpureiflorum <small>Morillo</small>
  • Cynanchum purpureum <small>(Pall.) K.Schum.</small>
  • Cynanchum pusilum <small>Grubov</small>
  • Cynanchum pycnoneuroides <small>Choux</small>
  • Cynanchum racemosum <small>(Jacq.) Jacq.</small>
  • Cynanchum radians <small>(Forssk.) Lam.</small>
  • Cynanchum radiatum <small>Jum. & H.Perrier</small>
  • Cynanchum rauhianum <small>Desc.</small>
  • Cynanchum registanense <small>Jayanthi</small>
  • Cynanchum rensonii <small>(Pittier) Woodson</small>
  • Cynanchum repandum <small>(Decne.) K.Schum.</small>
  • Cynanchum resiliens <small>(B.R.Adams & R.W.K.Holland) Goyder</small>
  • Cynanchum revoilii <small>(Franch.) Khanum & Liede</small>
  • Cynanchum riometense <small>Sundell</small>
  • Cynanchum rioparanense <small>Sundell</small>
  • Cynanchum rossii <small>Rauh</small>
  • <small>(Turcz.) Liede & Khanum</small>
  • Cynanchum roulinioides <small>(E.Fourn.) Rapini</small>
  • Cynanchum rubricoronae <small>Liede</small>
  • Cynanchum rungweense <small>Bullock</small>
  • Cynanchum sahyadricum <small>(Ansari & Hemadri) Liede & Khanum</small>
  • Cynanchum sarcomedium <small>Meve & Liede</small>
  • Cynanchum schistoglossum <small>Schltr.</small>
  • Cynanchum scopulosum <small>Bosser</small>
  • Cynanchum sessiliflorum <small>(Decne.) Liede</small>
  • Cynanchum sigridiae <small>Meve & M.Teissier</small>
  • Cynanchum sinoracemosum <small>M.G.Gilbert & P.T.Li</small>
  • Cynanchum socotranum <small>(Lavranos) Meve & Liede</small>
  • Cynanchum somaliense <small>(N.E.Br.) N.E.Br.</small>
  • Cynanchum staubii <small>Bosser</small>
  • Cynanchum stenospira <small>K.Schum.</small>
  • Cynanchum stoloniferum <small>(B.R.Adams & R.W.K.Holland) Goyder</small>
  • Cynanchum subpaniculatum <small>Woodson</small>
  • Cynanchum subtilis <small>Liede</small>
  • Cynanchum suluense <small>Schltr.</small>
  • Cynanchum sumbawanum <small>Warb.</small>
  • Cynanchum surrubriflorum <small>W.D.Stevens</small>
  • Cynanchum szechuanense <small>Tsiang & H.D.Zhang</small>
  • Cynanchum tamense <small>Morillo</small>
  • Cynanchum thruppii <small>(Oliv.) Khanum & Liede</small>
  • Cynanchum toliari <small>Liede & Meve</small>
  • Cynanchum trollii <small>Liede & Meve</small>
  • Cynanchum tsaratananense <small>Choux</small>
  • Cynanchum tuberculatum <small>(Blume) Boerl.</small>
  • Cynanchum tunicatum <small>(Retz.) Alston</small>
  • Cynanchum umtalense <small>Liede</small>
  • Cynanchum unguiculatum <small>(Britton) Markgr.</small>
  • Cynanchum vanlessenii <small>(Lavranos) Goyder</small>
  • Cynanchum verrucosum <small>(Desc.) Liede & Meve</small>
  • Cynanchum viminale <small>(L.) L.</small>
  • Cynanchum violator <small>R.W.Holm</small>
  • Cynanchum virens <small>(E.Mey.) D.Dietr.</small>
  • Cynanchum wallichii <small>Wight</small>
  • Cynanchum warburgii <small>Schltr.</small>
  • Cynanchum wilfordii <small>(Maxim.) Hook.f.</small>
  • Cynanchum zeyheri <small>Schltr.</small>

;Former species

  • Cynanchum auriculatum = Vincetoxicum auriculatum
  • Cynanchum arizonicum = Metastelma arizonicum – Arizona swallow-wort or Arizona climbing milkweed
  • Cynanchum utahense = Funastrum utahense – Utah swallow-wort or Utah vine milkweed

References

  • Cynanchum at Flora of China