Eupatorium sessilifolium


Eupatorium sessilifolium, commonly called upland boneset or sessile-leaved boneset, is a North American plant species in the sunflower family. It is native to the eastern and central United States, found from Maine south to North Carolina and Alabama, and west as far as Arkansas, Kansas, and Minnesota.

Description

Eupatorium sessilifolium is a perennial herb with stems that are sometimes more than 100 centimeters tall. They are produced from a woody underground caudice or short rhizome. The top of the stems, where the branching begins to the flower heads, have short hairs, while the lower part of the stems have no hairs. The leaves are arranged in opposite pairs and are toothed. The leaf bases are rounded and the leaves are sessile, but they do not clasp around the stem. The foliage is dotted with glands. Eupatorium sessilifolium blooms in August and September, and the small inflorescences are branched and composed of widely spaced, tiny white flower heads in corymbiform arrays. The heads typically have five or six disc florets per head, but no ray florets.
Upland boneset is a threatened species in Michigan, and legally protected in that state.

Hybrids

As is common in Eupatorium, E. sessilifolium can form hybrids with other species in the genus. In particular, Eupatorium godfreyanum is a hybrid of E. sessilifolium and Eupatorium rotundifolium.