RIGID GOLDENROD, Solidogo rigida L. 1, lower part of plant; 2, upper part of plant; 3, flower head; 4, seed. Perennial, reproducing by seeds and by persistence of a stout, branched base of the stem. Stem coarse, slightly hairy, up to 5 feet (1.5 m) tall. Leaves alternate, stiff and thick, grayish hairy, margins smooth or with shallowly rounded teeth; lower leaves longer petioled than upper, upper may be without petioles. Flowers terminal in dense heads, large with 30 to 40 yellow flowers per head. Fruits 1-seeded (achenes), smooth or hairy at tips, with 10 to 15 ridges on the surface. Found in dry, gravelly open places of woods or on prairies.