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Rudbeckia
See list of 6 species in this genusReference: Urbatsch and Cox (2006).
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1a. Pappus absent; style appendages elongate and pointed; chaff sharply acute to acuminate and hispidulous near the apex; leaf blades toothed to entire, but not lobed
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2a. Plants biennial or short-lived perennial, with basal tufts of leaves; leaves basally disposed, decreasing in size upwards, the lower borne on evident petioles
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2b. Plants annual, lacking basal tufts of leaves; leaves chiefly cauline, remaining relatively constant in size until near base of capitulescence, all sessile or subsessile
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1b. Pappus present, represented by a minute crown up to 0.2 mm long; style appendages short and blunt; chaff blunt to acute at apex (tipped by a cusp in R. triloba), glabrous or minutely downy-pubescent near apex; lower leaf blades with 3 or more prominent lobes or entire to toothed in R. fulgida
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3a. Leaf blades not lobed; chaff 2.5–4 mm long
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3b. Lower leaf blades with 3 or more prominent lobes; chaff 4–6.5 mm long
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4a. Chaff tipped by a glabrous cusp; rays 1–2 (–2.5) cm long; plants biennial or infrequently short-lived perennial, lacking rhizomes and leafy offshoots
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4b. Chaff obtuse to acute at apex, minutely downy-pubescent near apex; rays 2–6 cm long; plants perennial from rhizomes that produce leafy offshoots
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5a. Disk flowers yellow; stem ± glabrous; leaf blade surfaces lacking sessile glands; cypsela body flat, obliquely attached to receptacle
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5b. Disk flowers dark brown to purple (rarely yellow); stem densely short-pilose, at least in the apical half; leaf blade surfaces with sessile glands; cypsela body equilaterally quadrangular, basally attached to receptacle
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Each photo represents one species in this genus.