Conyza bonariensis (L.) Cronq.
Family: Asteraceae
asthmaweed,  more...
[Erigeron bonariensis L.,  more]
Conyza bonariensis image
Max Licher  
Plants erect, 10-100(-150+) cm, branched mostly distally. Leaves: faces ± densely strigose or hispidulous; proximal blades oblanceolate, 30-80(-120+) × 10-25+ mm, obscurely lobed to coarsely toothed or entire; distal narrowly oblanceolate to linear, 10-50 × 2-10 mm, obscurely toothed or entire. Heads usually in paniculiform to racemiform, rarely corymbiform arrays. Involucres 3.5-5 mm. Phyllaries usually strigose or hispidulous; outer greenish to purplish, lanceolate, shorter; inner stramineous to purplish, linear-attenuate (more chartaceous to scarious, less hairy). Receptacles 3-5 mm diam. in fruit. Pistillate florets 60-150+; corollas ± equaling or surpassing styles, laminae 0 or to 0.3 mm. Disc florets 8-12+. Cypselae pale tan, 1-1.5 mm, faces glabrous or sparsely strigillose; pappi of 15-25+, pinkish, sordid, or tawny bristles 3-4+ mm. 2n = 54. Flowering year round, mostly late summer-fall. Disturbed sites, along roads and streets; 0-500 m; introduced; Ala., Ariz., Calif., Fla., Ga., La., Miss., N.Mex. N.C., Oreg., S.C., Tex., Utah, Va.; South America. Conyza bonariensis is widespread in tropical and warm-temperate regions of the world. It is thought to be native to South America.

Annual, 1-10+ dm, copiously and loosely hairy, habitally like no. 1 [Conyza canadensis (L.) Cronquist], or often with some of the lateral branches elongate and overtopping the central axis; lower lvs in robust plants sometimes to 15 נ2 cm; heads larger than in no. 1, the disk often over 1 cm wide; invol 4-6 mm, copiously short-hairy; pistillate fls (50-)70-200+, with a very short or scarcely developed ray to 0.5 mm, this generally surpassed by the style and equaling to more often surpassed by the often tawny or reddish pappus; 2n=54. A weed in waste places, widespread in trop. Amer. and occasionally intr. in se. U.S., n. to Va. Summer. (C. floribunda; Erigeron b.; Leptilon b.)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.
FNA 2006, Wiggins 1964, Kearney and Peebles 1969
Duration: Annual Nativity: Non-Native Lifeform: Forb/Herb General: Introduced annual 10-40 cm tall with 1 to several stems from base and corymbosely branching above, herbage hirsute and slightly scabrous, grayish. Leaves: Linear, numerous, 1.5-4 mm wide, 1.5-9 cm long, shallowly dentate to entire. Flowers: Heads 6-8 mm in diameter, numerous, corymbosely arranged, peduncles 3-20 mm long, involucral bracts lance-subulate to linear-subulate, 4-6 mm long, greenish, hirsutulous, margins slightly scarious; inconspicuous ray flowers, ligules barely equaling or slightly surpassing pappus, 3-4.5 mm long, disk corollas 3-3.5 mm long, greenish yellow, slender tube 1.2 mm long, lobes narrowly lance-triangular, .2-.3 mm long. Fruits: Brownish cypselae, 1.2 mm long, faintly compressed, minutely and sparsely stiff hairs to glabrate, pappus bristles capillary 3-4 mm long, tawny or shining white in youth, reddish in age. Ecology: Found along irrigation ditches, river bottoms and occasionally as a roadside weed below 3,500 ft (1067 m); flowers June-September. Notes: This is a widespread weed, generally on disturbed, urban sites. Ethnobotany: Unknown, but C. canadensis has many uses. Etymology: Conyza is a name used by Theophrastus, Pliny, and Dioscorides, presumably from the Greek konops (flea), bonariensis means of or from Buenos Aires. Synonyms: Erigeron bonariensis, Erigeron crispus, Erigeron linifolius, Leptilon bonariense, Linnaeus linifolium Editor: SBuckley, 2010
Conyza bonariensis image
Max Licher  
Conyza bonariensis image
Max Licher  
Conyza bonariensis image
Patrick Alexander  
Conyza bonariensis image
Patrick Alexander  
Conyza bonariensis image
Patrick Alexander  
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image
Conyza bonariensis image