Eupatorium sessilifolium L. (redirected from: Eupatorium sessilifolium var. brittonianum)
Family: Asteraceae
[Eupatorium sessilifolium var. brittonianum Porter,  more...]
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Perennials, 50-100+ cm. Stems (from short caudices or rhizomes) single, sparsely branched distally, 5-10+ dm, glabrous or glabrate proximally, puberulent distally (among heads). Leaves usually opposite (distal sometimes alternate); simple, sessile; blades pinnately nerved, lanceolate to oblong, 70-150+ × 10-30 mm (lengths mostly 2-5 times widths), bases truncate to somewhat rounded, margins serrate, apices narrowly acute to acuminate, faces glabrate (scattered, fine hairs), gland-dotted. Heads in corymbiform arrays. Phyllaries 10-15 in 2-3 series, elliptic to oblong, 2-5 × 0.5-1.5 mm, apices rounded to acute (not mucronate), abaxial faces villous to puberulent, gland-dotted. Florets 5; corollas 3-3.5 mm. Cypselae 2-3 mm; pappi of 30-40 bristles 3-4 mm. 2n = 20, 30.

Flowering Jul-Sep. Dry, open, edges of mesic woods; 20-300+ m; Ala., Ark., Conn., Del., Ga., Ill., Ind., Iowa, Kans., Ky., Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.

From Flora of Indiana (1940) by Charles C. Deam

Infrequent in many parts of the state. It is generally found on high, wooded ridges and in dry, sandy woods. It is usually common where it is found.

Plants 6-15 dm, single-stemmed from a crown or short caudex, puberulent in the infl, the herbage otherwise glabrous except that the lvs are gland-dotted; lvs opposite, sessile or subsessile, lanceolate, usually broadly rounded at the base, serrate, acuminate or long-acute, mostly 7-18 נ1.5-5 cm, 2.5-7 times as long as wide, the venation strictly pinnate; invol 4.5-6.5 mm, its bract imbricate, broadly rounded to merely obtuse, villous-puberulent and usually also atomiferous-glandular; fls 5(6), white; 2n=20, 30. Woods, especially in sandy, acid soils; s. N.H. to se. Minn., s. to Ga. and Ark. Aug., Sept.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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