Conyza canadensis

(Linnaeus) Cronquist

Bull. Torrey Bot. Club 70: 632. 1943.

Common names: Vergerette du Canada
Illustrated
Basionym: Erigeron canadensis Linnaeus Sp. Pl. 2: 863. 1753 (as canadense)
Synonyms: Conyza canadensis var. glabrata (A. Gray) Cronquist Conyza canadensis var. pusilla (Nuttall) Cronquist Conyza parva E. canadensis var. pusillus (Nuttall) B. Boivin
Treatment appears in FNA Volume 20. Treatment on page 350. Mentioned on page 349.

Plants erect, (3–) 50–200 (–350+) cm, branched mostly distally. Leaves: faces usually glabrate (proximal margins ± ciliolate, hairs usually stiff, spreading and hispid on nerves, hairs erect); proximal blades oblanceolate to linear, 20–50 (–100+) × 4–10 (–15+) mm, toothed to entire; distal similar, smaller, entire. Heads usually in paniculiform, sometimes corymbiform arrays. Involucres 3–4 mm. Phyllaries usually glabrous, sometimes sparsely strigose (margins chartaceous to scarious); outer greenish to stramineous, lanceolate to linear, shorter; inner stramineous to reddish, lance-attenuate to linear. Receptacles 1–1.5 (–3) mm diam. in fruit. Pistillate florets 20–30 (–45+); corollas ± equaling or surpassing styles, laminae 0.3–1 mm. Disc-florets 8–30+. Cypselae uniformly pale tan to light gray-brown, 1–1.5 mm, faces sparsely strigillose; pappi of 15–25, white bristles 2–3 mm. 2n = 18.


Phenology: Flowering year round, mostly summer–fall.
Habitat: Disturbed places
Elevation: 0–2000 m

Distribution

V20-806-distribution-map.gif

Alta., B.C., Man., N.S., Ont., P.E.I., Que., Sask., Ala., Ariz., Ark., Calif., Colo., Conn., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo., Mexico, Central America, in South America, Europe, Asia, Africa

Discussion

Conyza canadensis is thought to be native to North America and is now widely adventive, e.g., in South America, Europe, Asia, and Africa. Plants with stems glabrous and phyllaries red-tipped are sometimes treated as var. pusilla; similar plants with stems glabrous and phyllaries stramineous (not red-tipped) are sometimes treated as var. glabrata.

Selected References

None.

Lower Taxa

None.
... more about "Conyza canadensis"
strigose +, hispidulous +, hirsutulous +  and glabrous +
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
corymbiform +  and paniculiform +
indeterminate +  and determinate +
John L. Strother +
(Linnaeus) Cronquist +
decurrent +
Erigeron canadensis +
compound +  and simple +
mostly lanceolate;oblanceolate or linear +
rugulose +  and muricate +
barbellulate +  and barbellate +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Vergerette du Canada +
not 2-lipped +  and actinomorphic +
yellowish +, ochroleucous +, white +  and purplish +
20 +  and 150 +
surpassing styles +  and equaling +
beaked +, 2-ribbed +  and 5-ribbed +
uniformly pale tan +  and light gray-brown +
oblong +  and elliptic +
fertile +  and bisexual +
fertile +  and bisexual +
Alta. +, B.C. +, Man. +, N.S. +, Ont. +, P.E.I. +, Que. +, Sask. +, Ala. +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Fla. +, Ga. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Mont. +, Nebr. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Okla. +, Oreg. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tex. +, Utah +, Vt. +, Va. +, Wash. +, W.Va. +, Wis. +, Wyo. +, Mexico +, Central America +, in South America +, Europe +, Asia +  and Africa +
0–2000 m +
strigillose +  and glabrate +
winged +  and beaked +
dispersed +
Disturbed places +
corymbiform +, paniculiform +, disciform +  and radiate +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
stramineous +  and reddish +
lance-attenuate +  and linear +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
spreading;erect +
deltate +
dentate to pinnatifid +  and entire +
entire +, toothed +  and lobed +
membranous +
greenish +  and stramineous +
2-carpellate +
white +, tawny +  and sordid +
persistent +
Flowering year round, mostly summer–fall. +
strigose +  and glabrous +
lanceolate +  and linear +
unequal +  and larger +
5 cm50 mm <br />0.05 m <br /> (10 cm100 mm <br />0.1 m <br />) +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
toothed +  and entire +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Bull. Torrey Bot. Club +
styliferous +, neuter +  and pistillate +
bearing subulate enations +, hairy +  and bristly +
concave;usually flat;conic +
exalbuminous +
Illustrated +
strigose +, strigillose +, hispidulous +, hispid +  and glabrous +
appendaged +  and truncate +
papillate +  and smooth +
Conyza canadensis var. glabrata +, Conyza canadensis var. pusilla +, Conyza parva +  and E. canadensis var. pusillus +
Conyza canadensis +
species +
120 cm1,200 mm <br />1.2 m <br /> (350 cm3,500 mm <br />3.5 m <br />) +
10 cm100 mm <br />0.1 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
200 cm2,000 mm <br />2 m <br /> (350 cm3,500 mm <br />3.5 m <br />) +