Solidago sect. Ptarmicoidei
Sida 21: 756. 2004.
Leaves: basal (rosettes) usually present at flowering, largest; petiole bases or vasculature persisting on rhizomes; proximalmost cauline petiolate, often present but withered at flowering; proximal and distal usually with 1 prominent nerve (multiple nerves proximally in S. riddellii). Heads in flat-topped to rounded corymbiform arrays, sometimes glomerulate. Phyllaries striate with 3–7 nerves (except S. ptarmicoides), eglandular. Pappi bristles in 2 series (outer not clavate, inner longest, somewhat to strongly clavate).
Species 6 (6 in the flora).
|1||Leaves, stems and peduncles moderately to densely short-hairy; distal cauline leaf bladesovate, flat, never folded along midrib||Solidago rigida|
|1||Leaves, stems, and peduncles glabrous or sparsely hairy; distal leaf blades linear to lanceolate, sometimes folded along midrib||> 2|
|2||Rays white (rarely cream); leaf blades linear, stiff, glabrous or sparsely hairy||Solidago ptarmicoides|
|2||Rays yellow; leaf blades linear to linear-lanceolate, stiff or flexible, glabrous||> 3|
|3||Rays 1–4, peduncles usually sparsely to moderately strigillose; Arkansas, Louisiana, Mississippi, Oklahoma, Texas||Solidago nitida|
|3||Rays 6–12, peduncles glabrous or moderately strigillose; Manitoba, midwestern and Great Lakes states s to e Missouri||> 4|
|4||Involucres (5.5–)6–8(–9) mm; proximal and mid cauline leaves usually 3-nerved (sometimes obscurely), the 2 prominent lateral nerves arising proximally and running alongside midnerve for some distance before abruptly diverging; heads usually 10–30(–50)(–100+ rarely, in aberrant plants); plants 30–60+ cm; rays occasionally lighter yellow with age (damp,interdunal hollows, limestone alvars, Michigan, Ontario)||Solidago houghtonii|
|4||Involucres 4–6 mm; mid and distal cauline leaves not 3-nerved or if so then nerves parallel and not abruptly diverging; heads usually (10– on shorter stems)50–400; plants 40–120 cm||> 5|
|5||Leaves flat, only 1 nerve prominent; arrays corymbiform; dunes, marshes, along rivers,Great Lakes area, New York to Illinois and Wisconsin||Solidago ohioensis|
|5||Leaves folded along midrib and with (2–)3–8 prominent nerves at base; arrays somewhat paniculiform with rounded corymbiform branches; moist ground, sw Ontario toWisconsin and se Manitoba, sw to e Missouri||Solidago riddellii|