B. rlexuosum: tuberous stems erect, slender, glabrous, 1-2 feet high, with a few forked branches; leaves few decaying early, thrice ternate, the divisions short, narrow, pointed, entire or three-lobed; stem-leaves few, with narrow-linear divisions, the central lobe of each segment much longer than the lateral ones; umbels terminal, or one opposite the last leaf, of 6-10 rays with general involucres of 1-3 bracts, the partial ones more numerous. - Woods and pastures. Fl. May, June.