Eupatorium sessilifolium
Encyclopedia
Eupatorium sessilifolium, commonly called Upland Boneset or Sessile-leaved Boneset, is a herbaceous perennial plant in the family Asteraceae
. This species is native to eastern North America, where it blooms in late summer with white flowers.
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 (lacking stalks), but they do not clasp around the stem. The foliage is dotted with glands. Eupatorium sessilifolium blooms in August and September (July in the southern part of its range), and the small inflorescence
s are branched and composed of widely-spaced, white flower heads in corymbiform arrays. The heads typically have five or six disc florets per head, and no ray florets.
Upland Boneset has a wide distribution within the eastern and central United States, but is endangered in Minnesota
, New Hampshire
, and Vermont
. It is a threatened species in Michigan
, and legally protected in that state.
, E. sessilifolium can form hybrids with other species in the genus. In particular, Eupatorium godfreyanum is a hybrid of E. sessilifolium and Eupatorium rotundifolium
(although it reproduces by apomixis
and thus can be found outside the range of the two parent species).
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
. This species is native to eastern North America, where it blooms in late summer with white flowers.
Description
Upland Boneset has stems that grow from 50 to over 100 centimeters tall. They are produced from a caudiceCaudex
A caudex is a form of stem morphology appearing as a thickened, short, perennial stem that is either underground or near ground level . It may be swollen for the purpose of water storage, especially in xerophytes...
or short rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
. 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 (lacking stalks), but they do not clasp around the stem. The foliage is dotted with glands. Eupatorium sessilifolium blooms in August and September (July in the southern part of its range), and the small inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s are branched and composed of widely-spaced, white flower heads in corymbiform arrays. The heads typically have five or six disc florets per head, and no ray florets.
Upland Boneset has a wide distribution within the eastern and central United States, but is endangered in Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, New Hampshire
New Hampshire
New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian...
, and Vermont
Vermont
Vermont is a state in the New England region of the northeastern United States of America. The state ranks 43rd in land area, , and 45th in total area. Its population according to the 2010 census, 630,337, is the second smallest in the country, larger only than Wyoming. It is the only New England...
. It is a threatened species in Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, and legally protected in that state.
Hybrids
As is common in EupatoriumEupatorium
Eupatorium is a genus of flowering plants in the aster family, Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennial plants growing to 0.5–3 m tall. A few are shrubs. The genus is native to temperate regions of the Northern Hemisphere....
, E. sessilifolium can form hybrids with other species in the genus. In particular, Eupatorium godfreyanum is a hybrid of E. sessilifolium and Eupatorium rotundifolium
Eupatorium rotundifolium
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...
(although it reproduces by apomixis
Apomixis
In botany, apomixis was defined by Winkler as replacement of the normal sexual reproduction by asexual reproduction, without fertilization. This definition notably does not mention meiosis...
and thus can be found outside the range of the two parent species).