Botany picture of the unspecified time unit #1

Cynanchum diemii (Apocynaceae: Asclepiads). In 2009, I was on a conference trip in Argentina with a German colleague, and we stayed a few days longer to explore the area around Bariloche. We were walking through a forest where nothing much seemed to be in flower - it was essentially very late winter - when we suddenly walked through a cloud of intense, sickly sweet scent. Searching around us, we finally located this delightful vine with small yellow flowers as the source.