proteranthous UK /ˌpɹəʊtəɹˈænθəs/US /ˌproʊtəɹˈænθəs/ adjective2 •(rare) Of a plant: having flowers that appear earlier than the leaves.Proteranthous (-us). Where flowering precedes leafing. — 1879 •(rare) Of a plant: having leaves that appear earlier than the flowers.Proteranthous; when leaves appear before the flowers. — 1836