Eupatorium altissimum

Linnaeus

Sp. Pl. 2: 837. 1753.

Common names: Tall thoroughwort
Endemic
Treatment appears in FNA Volume 21. Treatment on page 465. Mentioned on page 464, 466, 549.

Perennials, 50–150+ cm. Stems (from short caudices or stout rhizomes) single, sparsely branched distally, pubescent throughout (nodes sometimes with galls). Leaves usually opposite (nodes often appearing leafy, lateral buds producing 2+ pairs of leaves); sessile or subsessile; blades strongly 3-nerved from bases, lance-elliptic to oblanceolate, 50–120 × 5–20 mm, bases ± cuneate, margins entire proximally, serrate distally, apices acuminate, faces puberulent or villous, glanddotted. Heads in corymbiform arrays. Phyllaries 8–10 in 2–3 series, oblong, 1–4 × 0.5–1.5 mm, (bases tapered) apices rounded to acute (not mucronate), abaxial faces pubescent throughout. Florets 5; corollas 3–3.5 mm. Cypselae 2–3 mm; pappi of 30–40 bristles 3.5–4 mm. 2n = 20, 30, 40.


Phenology: Flowering Jul–Sep.
Habitat: Clearings, open woods, thickets
Elevation: 20–400 m

Distribution

V21-1160-distribution-map.gif

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

Discussion

Eupatorium altissimum occurs in sexual diploid populations in the Ozark region of Missouri and Arkansas, and as apomictic polyploids elsewhere throughout its range. It occurs almost exclusively on limestone soils, where it is often accompanied by (and sometimes misidentified as) Brickellia eupatorioides, which has 10-ribbed cypselae and plumose pappus bristles. Eupatorium altissimum hybridizes with E. serotinum.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Eupatorium altissimum"
40 +, 30 +  and 20 +
not tailed +, truncate +, rounded +  and obtuse +
rounded;acute +
scarious +
usually ovate +  and lanceolate +
usually terete +  and clavate +
diffuse +  and dense +
indeterminate +  and determinate +
Kunsiri Chaw Siripun +  and Edward E. Schilling +
Linnaeus +
puberulent +
cuneate +
enlarged +
5 cm50 mm <br />0.05 m <br /> (12 cm120 mm <br />0.12 m <br />) +
dissected +, lobed +, toothed +  and entire +
lance-elliptic;oblanceolate +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
papillate +  and rugose +
(4-)5-angled;10-ribbed +
filiform +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Tall thoroughwort +
pinkish +  and white +
0.3 cm3 mm <br />0.003 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
prismatic +
fertile +  and bisexual +
Ont. +, Ala. +, Ark. +, Conn. +, Fla. +, Ga. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Nebr. +, N.J. +, N.Y. +, N.C. +, Ohio +, Okla. +, Pa. +, S.C. +, Tenn. +, Tex. +, Va. +, W.Va. +  and Wis. +
20–400 m +
villous +  and puberulent +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Clearings, open woods, thickets +
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 +
subsessile +  and sessile +
triangular +
serrate +  and entire +
2-carpellate +
persistent +
Flowering Jul–Sep. +
nerved +  and 2-3-nerved +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
8 +  and 10 +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
bearing subulate enations +, hairy +  and bristly +
convex;flat +
exalbuminous +
appendaged +  and truncate +
hirsutulous +
papillate +
Compositae +
Eupatorium altissimum +
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 +