Cynanchum laeve; Asclepiadaceae (milkweed family)
Another morning spent clambering over the rock bluffs, another plant I didn’t recognize and expected to be an alien, and another case of going to the internet to identify it because it wasn’t in any of my books. This milkweed relative is native to the eastern US. Although considered weedy and invasive by some authorities, it is listed as rare in the state of Pennsylvania. It will grow up to 15 feet long, vining and twining along other plants for support. As with the milkweeds, it will bleed an irritating, milky sap if cut or bruised. Apparently monarch butterflies like it.