Bidens aristosa showy beggar-ticks Asteraceae BIAR*; Bx, pb (DeCandido 2001); R (DeCandido 2001);


Bidens aristosa.Rick

Bidens aristosa.Rick (Accessed 12/2014).

Bidens aristosa is an annual or biennial herb 30-150 cm tall. 

Leaves opposite, pinnately divided, 5-15 cm long including stalk 1-3 cm , leaf segments linear, toothed or lobed. 

Flowers: ray flowers about 8, yellow, 1-2.5 cm long, disk 0.8-1.5 cm wide, basal bracts of flower head linear, 0.5-1 cm long, outer bracts shorter than inner bracts. 

Fruit dry, 1-seeded (achene), flat 0.5-0.7 cm long, margins slightly winged, fringed with hairs, usually topped by 2 barbed awns; blooming and fruiting Aug-Nov. 

Wetland status: FACW-. 

Frequency in NYC: Very infrequent. 

Origin: Midwestern USA. 

Habitat: Partly shady sites in moist to wet soil, pH 5-7 (USDA 2006).