Prenanthes alba (Nabalus albus) white lettuce; rattlesnake root Asteraceae PRAL; R, gb;


Prenanthes alba.K.

Prenanthes alba.© 2008 K. (Accessed 4/2014).

Prenanthes alba is a perennial herb 0.4 -1.7 m tall, stem stout, from thick root, sap milky, stem usually purplish with waxy-white bloom, smooth. 

Leaves alternate, variable, waxy-pale green, toothed to triangular with lobed base, lower leaves long-stalked, larger, upper leaves smaller shorter-stalked. 

Flowers whitish, 9-11, all rays, flower heads narrow, nodding, bracteate base 1-1.4 cm long, bracts usually 8, purplish or green, pale-waxy, minutely warty (use lens); inflorescence branched, narrow; blooming and fruiting Aug.-Sept. (Hough 1983). 

Fruit dry, seeds (achenes) cylindrical with a reddish-brown plume. 

Wetland status: FACU. 

Frequency in NYC: Very infrequent.

 Origin: Native. 

Habitat: Open, undisturbed woods. 

Notes: Recent DNA studies have classified all our Prenanthes as belonging to the genus Nabalus (Shilling et al. 2015).