round-leaved boneset (TVA, White's Creek Small Wild Area, Plants)

round-leaved boneset

Eupatorium rotundifolium

Summary ⁴

Eupatorium rotundifolium, commonly called Roundleaf thoroughwort, is a herbaceous perennial plant in Asteraceae native to the eastern states of the United States in an area from New Jersey to Oklahoma south to Texas to Florida. The stems grow from 40 to over 100 cm tall and are produced from short rhizomes. The inflorescences are composed of a large number of white flower heads with disc florets and no ray florets. Plants can be highly variable due to...

Comments ⁵

Eupatorium rotundifolium is one of the more variable species of the genus; its apparent propensity to hybridize with other species has led it to be described as a compilospecies and has complicated its delimitation. Hybrids with E. perfoliatum and E. sessilifolium are sufficiently distinctive to be treated here as distinctive entities (E. ×cordigerum and E. godfreyanum, respectively), and the varieties ovatum and scabridum have also been proposed to be of hybrid origin. The boundaries between varieties are indistinct and individual specimens may be difficult to place with confidence.

Description ⁶

Perennials, 40–100+ cm. Stems (from short rhizomes) single, sparsely branched distally, puber-ulent. Leaves usually opposite (distal sometimes alternate, lateral buds dormant or producing 1 pair of leaves); sessile or subsessile; blades ± 3-nerved, usually ± deltate to orbiculate, sometimes ovate, 15–50(–70) × 15–40(–60) mm (lengths mostly 1–2 times widths), bases broadly rounded to truncate, margins crenate to serrate, apices acute, faces puberulent to villous, gland-dotted. Heads in corymbiform arrays. Phyllaries 8–10 in 2–3 series, elliptic to oblanceolate, 2–6 × 0.5–1.5 mm, apices acute, abaxial faces puberulent, gland-dotted. Florets 5; corollas 3–4 mm. Cypselae 2–3 mm; pappi of 30–40 bristles 3.5–4 mm.

Sources and Credits

(c) Anita Gould, some rights reserved (CC BY-NC), uploaded by Anita Gould, http://www.flickr.com/photos/anitagould/47367450/
(c) Fritz Flohr Reynolds, some rights reserved (CC BY-SA), https://www.flickr.com/photos/fritzflohrreynolds/7883982214/
(c) dogtooth77, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/53817483@N00/4943387877/
Adapted by Jonathan (JC) Carpenter from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Eupatorium_rotundifolium
(c) Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/19791685
(c) Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/4942977

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