Eupatorium semiserratum

de Candolle in A. P. de Candolle and A. L. P. P. de Candolle

in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 177. 1836.

Common names: Smallflower thoroughwort
Endemic
Synonyms: Eupatorium cuneifolium var. semiserratum (de Candolle) Fernald & Griscom
Treatment appears in FNA Volume 21. Treatment on page 473. Mentioned on page 464, 469.

Perennials, 40–100+ cm. Stems (from short rhizomes) single, densely branched distally, puberulent throughout. Leaves usually opposite (distal sometimes alternate, lateral buds dormant or producing 1 pair of leaves); simple, sessile or subsessile; blades ± 3-nerved distal to bases, elliptic to lance-elliptic, (30–) 50–70 × 5–25 mm (lengths mostly 2–5 times widths), bases narrowly cuneate, margins usually serrate, apices acute, faces puberulent or villous, densely glanddotted. Heads in corymbiform arrays. Phyllaries 7–10 in 2–3 series, elliptic, 1–3 × 0.5–1 mm, apices rounded to acute (not mucronate), abaxial faces puberulent, glanddotted. Florets 5; corollas 2.5–3 mm. Cypselae 1.5–2 mm; pappi of 30–40 bristles 2.5–3 mm. 2n = 20.


Phenology: Flowering Aug–Sep.
Habitat: Moist to boggy, sandy, peaty soils, margins of pine flatwoods, gum swamps, bayheads, disturbed sites, roadsides
Elevation: 10–100+ m

Distribution

V21-1187-distribution-map.gif

Ala., Ark., Fla., Ga., La., Miss., N.C., S.C., Tenn.

Discussion

Eupatorium semiserratum has been included within E. glaucescens (E. cuneifolium); it is distinguished by its consistently smaller heads and stems that branch only within the capitulescences. It differs from the similar and sometimes sympatric E. lancifolium by its smaller heads, leaves 3-nerved distal to bases (rather than at bases), as well as preference for wetter habitats. It has been proposed that E. rotundifolium var. scabridum (E. pubescens) represents hybrids between E. semiserratum and E. rotundifolium; it also apparently hybridizes with E. hyssopifolium.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Eupatorium semiserratum"
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 +
de Candolle in A. P. de Candolle and A. L. P. P. de Candolle +
puberulent +
cuneate +
enlarged +
elliptic to lance-elliptic +
3 cm30 mm <br />0.03 m <br /> (5 cm50 mm <br />0.05 m <br />) +
5 cm50 mm <br />0.05 m <br /> (7 cm70 mm <br />0.07 m <br />) +
dissected +, lobed +, toothed +  and entire +
ovate;lanceolate or linear +
5mm;25mm +
papillate +  and rugose +
(4-)5-angled;10-ribbed +
filiform +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Smallflower 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. +, Fla. +, Ga. +, La. +, Miss. +, N.C. +, S.C. +  and Tenn. +
10–100+ m +
villous +  and puberulent +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Moist to boggy, sandy, peaty soils, margins of pine flatwoods, gum swamps, bayheads, disturbed 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 +
subsessile +, sessile +  and simple +
triangular +
2-carpellate +
persistent +
Flowering Aug–Sep. +
nerved +  and 2-3-nerved +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
7 +  and 10 +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. +
bearing subulate enations +, hairy +  and bristly +
convex;flat +
exalbuminous +
appendaged +  and truncate +
hirsutulous +
papillate +
Eupatorium cuneifolium var. semiserratum +
Eupatorium semiserratum +
Eupatorium +
species +
campanulate +
toothed +  and entire +
40 cm400 mm <br />0.4 m <br /> (100 cm1,000 mm <br />1 m <br />) +
vine +, shrub +  and subshrub +