Tripleurospermum inodorum (L.) Sch.-Bip

Chamomilla inodora (L.) Gilib. Exerc. Phyt. 179. 1792
Matricaria inodora L. Fl. Succ. ed. 2. 297. 1755.
Chrysanthemum Inodoriim L. Sp. PI. ed. 2. 1253. 1763.
Pyrethrum inodorum Moench, Meth. 597. 1794.
Tripleurospermum inodorum Schultz-Bip. Tanac. 32. 1844.
Dibolhrospermum agreste Knaf. Flora 29: 299. 1846.
Chamaemelum inodorum Vis. Osserv. Matric. 13. 1844.— Fl. Dalm. 2: 85. 1847.
Trallesia malricarioides Zumag. Fl. Ped. 1: 361. 1849.
A leafy annual; stem 2-4 dm. high, glabrous, striate, branched; leaves bipinnatifid, 3-6 cm. long, with linearfiliform, long and flaccid divisions, glabrous or nearly so; heads several, solitary at the ends of the branches; involucre saucer-shaped, 4 mm. high, 10-15 mm. broad; bracts in 2-3 series, subequal, linear or linear-oblong, obtuse, with white or light-brown scarious margins; receptacle convex, obtuse; ray-flowers 15-25; ligules white, 7-10 mm. long, 2-3 mm. wide; style-branches truncate; disk-corollas yellow, 2.5 mm. long; tube equaling the campanulate throat; lobes 5, lanceolate; achenes 1.5-2 mm. long, dark-brown when ripe, oblique, with 3 strong ribs on the inner side, rugose on the back and between the ribs; crown of pappus well developed, usually entire.
Type locality: Sweden.
Distribution: Newfoundland to Pennsylvania and Ontario; Oregon and Idaho; adventive or naturalized from Europe.