This taxon name is not current. The available references for this name are:
Ischnostemma King & Gamble is more recently known as Vincetoxicum Wolf
Reason See S. Liede-Schumann & U. Meve in Phytotaxa 369:131 (2018)
See also: A longer explanation of these and other terms in our Plant Names Primer.
A taxon name that is no longer current will retain its ‘Threatened’, ‘Extinct’, or ‘Extinct in the Wild’ status until a new name has been published in a Biodiversity Conservation Order.