=Star Thistle.= _Centaurea solstitialis_ L. Achene cream white to mottled brown, flattened, oval about 2 mm. long; scar of attachment in a notch of one edge above the rounded base, apex truncate with a small tubercle in the middle. Found in seeds of alfalfa. A ragged plant from Europe. [Illustration: Fig. 189.] =Ox-eye Daisy.= _Chrysanthemum Leucanthemum_ L. Flowers white; achenes brown or black with ten white conspicuous vertical ribs, narrowly obovate 1.5-1.8 mm. long, bearing a tubercle at the apex. Introduced from Europe. Becoming common. A prominent weed in old pastures and meadows. [Illustration: Fig. 190.] =Chickory.= _Chichorium Intybus_ L. Flowers yellow; achenes light brown, more or less mottled or spotted with black, straight or curved, 4-5 angled, flattened, apex truncate crowned with a double row of minute scales. Achenes 2.5-3 mm. long. Introduced from Europe. [Illustration: Fig. 191.] =Canada Thistle.= _Cirsium arvense_ (L.) Scop. _Carduus arvensis_ (L.) Robs. Flowers purple or white; achenes smooth, light brown, curved or straight, narrowly obovoid or oblong, slightly flattened, 2-3 mm. long, apex truncate, cup-shaped with a tubercle in the center. Introduced from Europe. A weed of first rank. [Illustration: Fig. 192.] =Bull Thistle.= _Cirsium lanceolatum_ (L.) Hill. _Carduus lanceolatus_ L. Flowers purple; achenes smooth, nearly white, with sharp vertical brown stripes, slightly flattened, obovate or oblong, usually curved near the apex, 3-4 mm. long, apex truncate with a large tubercle in the center. Introduced from Europe. [Illustration: Fig. 193.] =Narrow leaved Hawksbeard.= _Crepis tectorum_ L. Flowers yellow; achene chestnut brown, straight or curved, linear, ribs 10, smooth or rugose; 3.4 mm. long. Introduced from Europe. [Illustration: Fig. 194.] =Fire-weed.= _Erechtites hieracifolia_ (L.) Raf. Achenes brown, linear, 2.2-2.8 mm. long, flattened, straight or curved, having ten vertical ribs between which are minute white oppressed hairs, the extremities truncate, wider than the narrow portion beneath, the apex white with a tubercle projecting from the center of a minute cup. Native to this country. Not of much importance. =Annual Fleabane.= _Erigeron annuus_ (L.) Pers. Flowers white; achenes smooth, shining, brownish white, translucent, flattened, obovate or oblong, .7-.9 mm. long, bearing at the apex a whorl of very small diverging bristles, the longest ones having been rubbed off. Faint traces of a few oppressed hairs may be seen under a good lens. Native to this country and a very prominent weed in thin meadows. [Illustration: Fig. 195.]