Heads several-flowered, radiate; disk-flowers often sterile. Involucral bracts imbricated in 2 or more rows, the outer shorter. Receptacle flat, naked. Achenes fusiform or compressed; pappus of 5 or fewer thin nerveless paleæ, alternating with rough bristly awns, or these wanting.--Low southwestern branching annuals, with narrow entire leaves and solitary terminal heads; ray white or purple. (Χαίτη, _a bristle_, and πάππος, _pappus_.) 1. C. asteroìdes, DC. Slender, 2--10´ high, pubescent; involucres narrow, 2´´ long; rays 5--12; achenes pubescent.--Dry grounds, Vernon Co., Mo., and southward. 22. BOLTÒNIA, L'Her. Heads many-flowered, radiate; the rays numerous, pistillate. Scales of the hemispherical involucre imbricated somewhat in 2 rows, appressed, with narrow membranaceous margins. Receptacle conical or hemispherical, naked. Achenes very flat, obovate or inversely heart-shaped, margined with a callous wing, or in the ray 3-winged, crowned with a pappus of several minute bristles and usually 2--4 longer awns.--Perennial and bushy-branched smooth herbs, pale green, with the aspect of Aster; the thickish leaves chiefly entire, often turned edgewise. Flowers autumnal; disk yellow; rays white or purplish. (Dedicated to _James Bolton_, an English botanist of the last century.) [*] _Heads middle-sized, loosely corymbed._ 1. B. asteroìdes, L'Her. Stems 2--8° high; leaves lanceolate; involucral scales acuminate; pappus of few or many minute bristles and 2 awns or none. (B. glastifolia, _L'Her._, the awned form.)--Moist places along streams; Penn. to Ill., and southward to Fla. Sept., Oct.--Var. DECÚRRENS, Engelm., a large form with the leaves alate-decurrent upon the stem and branches. Mo. (_Eggert_). 2. B. latisquàma, Gray. Heads rather larger; involucral scales oblong to ovate, obtuse or mucronate-apiculate; pappus-awns conspicuous.--W. Mo. and Kan. [*][*] _Heads small, panicled on the slender branches._ 3. B. diffùsa, L'Her. Stem diffusely branched; leaves lance-linear, those on the branchlets very small and awl-shaped; rays short, mostly white; pappus of several very short bristles and 2 short awns.--Prairies of S. Ill. (_Vasey_), and southwestward. Aug.--Oct. 23. TOWNSÉNDIA, Hook. Heads many-flowered, the numerous ray-flowers (violet to white) in a single series, fertile. Involucre broad, the lanceolate scariously margined scales imbricated in several series. Receptacle flat, naked. Achenes obovate or oblong, flattened, with thickish margins and beset with forked-capitellate hairs; pappus a single row of long awns or coarse rigid bristles, or reduced in the ray to chaffy scales.--Low scarcely caulescent herbs, with linear to spatulate entire leaves and large heads. (Named for _David Townsend_, botanical associate of Dr. Darlington of Penn.) 1. T. serìcea, Hook. Acaulescent silky-pubescent perennial; heads sessile, solitary or few, ½--1´ high; ray-pappus mostly bristly.--Dry plains, central Neb., north and westward. April, May.