Eupatorium serotinum

Michaux

Fl. Bor.-Amer. 2: 100. 1803.

Common names: Lateflowering thoroughwort
IllustratedEndemic
Treatment appears in FNA Volume 21. Treatment on page 473. Mentioned on page 463, 465, 466, 468, 470, 471, 472, 474.

Perennials, 50–150+ cm. Stems (from short caudices) single, sparsely to densely branched distally, pubescent throughout (sometimes reddish to purplish). Leaves opposite; petiolate (petioles 10–25 mm); blades ± 3-nerved, lanceolate, 20–90+ × 5–40 mm, bases rounded to slightly oblique, margins entire or serrate, apices acute, faces puberulent, glanddotted. Heads in corymbiform arrays. Phyllaries 8–12 in 1–2 series, elliptic to oblong, 1–3 × 0.5–1 mm, apices slightly rounded to acute, abaxial faces puberulent, glanddotted. Florets 9–15; corollas 2.5–3 mm. Cypselae 1–1.5 mm; pappi of 20–30 bristles 2–2.5 mm. 2n = 20.


Phenology: Flowering Aug–Oct.
Habitat: Moist or dry, open sites, roadsides
Elevation: 10–400+ m

Distribution

V21-1188-distribution-map.gif

Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va., Wis.

Discussion

Eupatorium serotinum has a wide distribution and is often abundant where it occurs. It includes only sexual, diploid populations. It is known to hybridize with E. perfoliatum. An introduction of E. serotinum in southeastern Ontario apparently is local and may not have persisted.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Eupatorium serotinum"
not tailed +, truncate +, rounded +  and obtuse +
scarious +
usually ovate +  and lanceolate +
usually terete +  and clavate +
diffuse +  and dense +
indeterminate +  and determinate +
Kunsiri Chaw Siripun +  and Edward E. Schilling +
Michaux +
puberulent +
rounded +  and slightly oblique +
enlarged +
2 cm20 mm <br />0.02 m <br /> (9 cm90 mm <br />0.09 m <br />) +
dissected +, lobed +, toothed +  and entire +
lanceolate +
5mm;40mm +
papillate +  and rugose +
(4-)5-angled;10-ribbed +
filiform +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Lateflowering thoroughwort +
pinkish +  and white +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
prismatic +
fertile +  and bisexual +
Ala. +, Ark. +, Conn. +, Del. +, Fla. +, Ga. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Nebr. +, N.J. +, N.Y. +, N.C. +, Ohio +, Okla. +, Pa. +, R.I. +, S.C. +, Tenn. +, Tex. +, Va. +, W.Va. +  and Wis. +
10–400+ m +
puberulent +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Moist or dry, open sites, roadsides +
in usually determinate , rarely indeterminate , arrays +  and singly +
indeterminate +
each +  and sessile +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
obconic;ellipsoid +
triangular +
serrate +  and entire +
2-carpellate +
persistent +
Flowering Aug–Oct. +
nerved +  and 2-3-nerved +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
8 +  and 12 +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Fl. Bor.-Amer. +
bearing subulate enations +, hairy +  and bristly +
convex;flat +
exalbuminous +
Illustrated +  and Endemic +
appendaged +  and truncate +
hirsutulous +
papillate +
Compositae +
Eupatorium serotinum +
Eupatorium +
species +
campanulate +
toothed +  and entire +
50 cm500 mm <br />0.5 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
vine +, shrub +  and subshrub +