BUTTERFLY - WEED (Asctepias tuberosa), a North American plant of the milkweed family (Asclepiadaceae), known also as pleurisy-root, orange-root and orange milkweed. It is native to dry fields, mostly in limestone soil, from Maine to Ontario and Minnesota and southward to Florida, Texas, Arizona and Chihuahua. The butterfly-weed is a stout, rough haired perennial, with long hori zontal roots. The usually erect, somewhat branching stem, I ft.
to 3 ft. high, is very leafy throughout, and about midsum mer bears numerous clusters of bright orange flowers. Unlike most milkweeds, this plant has a very scanty milky juice. The root has been used in medicine, especially for pulmonary affec tions. Butterfly-weed is often planted in wild gardens and is sparingly grown as a border plant.