1 Perennials or subshrubs or shrubs, 1-8 dm tall; [OK & TX, southwards and westwards].

..2 Pistillate involucres 7-9 mm long; phyllaries keeled; leaves gland-dotted on lower and upper sides; leaf margins finely undulate

..2 Pistillate involucres 9-14 mm long; phyllaries not keeled; leaves without glands; leaf margins not undulate

1 Shrubs, (3-) 10-60 dm tall; [collectively widespread]

....3 Leaves 1-2 (-5) mm wide; stems glabrous.

......4 Leaves without glands; pappi 6-8 mm long in fruit; [NC along coast west to LA]

......4 Leaves gland-dotted; pappi 8-12 mm long in fruit; [TX and OK southwards]

....3 Leaves (3-) 5-40 mm wide; stems glabrous to minutely pubescent or scurfy.

........5 Heads grouped in sessile (or subsessile) clusters of 1-4 heads, each cluster subtended by a normally sized or slightly reduced leaf; heads sessile; bracts (leaves) subtending head clusters usually broadly obovate or spatulate (L:W 1.5-3×) and also usually toothed; leaf glands on leaf undersurface only, small and inconspicuous under magnification

........5 Heads in paniculiform or umbelliform arrays of 10 to very many heads, the arrays including some reduced bracts subtending branches or head clusters, but with terminal groupings of heads mostly of 10+ heads above the last bract; heads pedunculate (short pedunculate or sessile in B. salicina); bracts in the inflorescence mainly untoothed and narrower than leaves below the inflorescence, lanceolate to narrowly elliptical, 3-7× as long as wide (except spatulate and 1-2× in Baccharis dioica); leaf glands on both upper and lower faces, large and usually conspicuous under magnification (less so in older specimens) (except finer and less conspicuous in Baccharis salicina).

..........6 All leaf blades entire (marginal teeth extremely rare); leaf apices broadly rounded to truncate or even retuse; pappi 3-6 mm long in fruit; [s. FL, s. LA]

..........6 At least some leaf blades toothed or lobed, rarely all entire, sometimes the distal ones especially entire; leaf apices acuminate, acute, or obtuse; pappi 3-12 mm long in fruit; [collectively widespread].

............ 7 Leaf margins of larger leaves finely serrate from base to tip (rarely entire); pappi 3-6 mm long in fruit; cypselas 5-nerved

............ 7 Leaf margins of larger leaves coarsely teeth mainly above the leaf midpoint; pappi 8-12 mm long in fruit.

............ ..8 Larger leaves lanceolate-elliptic to lanceolate to elliptic, mostly 2-5× as long as wide, 5-10 (-20) mm wide; pistillate involucres 5-9 mm high; staminate involucres 4-7 mm high; [OK & TX westwards].