WordNet sense 1 (Canadian dogbane yielding a tough fiber used as cordage by native Americans; used in folk medicine for pain or inflammation in joints):

Indian hemp, Apocynum cannabinum

WordNet sense 2 (North American perennial having pinkish flowers in loose cymes; used in folk medicine for pain or inflammation in joints):

common dogbane, Apocynum androsaemifolium, spreading dogbane