1) Birthwort 1) Purple trillium 2) Red trillium 3) Trillium 4) Trillium erectum 5) Wake-robin 6) Wood lily 
• (n.) An herbaceous plant (Trillium erectum), and its astringent rootstock, which is said to have medicinal properties.
Birth'root` noun (Botany) An herbaceous plant ( Trillium erectum ), and its astringent rootstock, which is said to have medicinal properties. 
Also calleda trillium, Trillium erectum, the roots of which were formerly used in medicine as an astringent. · any of certain other species of trillium.