Heads radiate, the rays pistillate and fertile, light yellow; invol of 4(5) relatively large and leafy bracts, united at base; receptacle conic, especially in fr, its bracts subtending rays as well as disk-fls, thin, partly clasping the achenes; disk-fls perfect and fertile, the cor-tube expanded at base and covering the top of the achene; style-branches flattened, with rather long, hairy appendage; achenes quadrangular or subterete, scarcely compressed; pappus of several short scales, or none; coarse, taprooted perennial herbs with clustered stems, opposite, ± toothed, often clasping lvs and few or solitary heads. 4, U.S., Mex.
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