''Eupatorium serotinum'', also known as late boneset or late thoroughwort, is a fall-blooming, perennial,

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

native to North America. ''Eupatorium serotinum'' ranges throughout most of the eastern United States, found in every coastal state from

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

and inland as far as

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

and

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

. There are reports of one small population in the Canadian Province of

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

, and other reports of the species on the south side of the

Río Grande The Rio Grande ( or ) in the United States or the Río Bravo (del Norte) in Mexico (), also known as Tó Ba'áadi in Navajo, is one of the principal rivers (along with the Colorado River) in the Southwestern United States and in northern Me ...

in northern Mexico. Like other members of the genus ''

Eupatorium ''Eupatorium'' is a genus of flowering plants in the family Asteraceae, containing from 36 to 60 species depending on the classification system. Most are Herbaceous plant, herbaceous perennial plant, perennials growing to tall. A few are shrubs ...

'', ''Eupatorium serotinum'' is about one to two meters (40–80 inches) tall. The leaves are typically ovate with serrate margins. The leaf arrangement is alternate, although it can be opposite at some upper nodes. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is a flat-topped

corymb Corymb is a botanical term for an inflorescence with the flowers growing in such a fashion that the outermost are borne on longer pedicels than the inner, bringing all flowers up to a common level. A corymb has a flattish top with a superficial re ...

of many small white

flower heads A pseudanthium (; : pseudanthia) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers ...

with 9–15

disc floret Asteraceae () is a large family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the order Asterales. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger fa ...

s but no

ray florets Asteraceae () is a large family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the order Asterales. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger fa ...

. ''Eupatorium serotinum'' grows in open sites (either dry or moist), and can hybridize with '' Eupatorium perfoliatum'' and other members of the genus ''Eupatorium''. Unlike wind-pollinated plants in this genus, ''E. serotinum'' is pollinated by insects. ''Eupatorium serotinum'' provides late-season nectar for

Monarch Butterflies The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. ...

. There is also evidence that

pyrrolizidine alkaloids Pyrrolizidine alkaloids (PAs), sometimes referred to as necine bases, are a group of naturally occurring alkaloids based on the structure of pyrrolizidine. Their use dates back centuries and is intertwined with the discovery, understanding, and ...

produced by ''Eupatorium serotinum'' are beneficial to Monarchs.

References

External links

Photo
from the Ozarks Regional Herbarium of

Missouri State University Missouri State University (MSU or MO State), formerly Southwest Missouri State University, is a public university in Springfield, Missouri, United States. Founded in 1905 as the Fourth District Normal School, it is the state's second-largest u ...

Photo of herbarium specimen at Missouri Botanical Garden, collected in Missouri in 1993

From the blog "Nadia's Backyard
a native plant blog in central Missouri. serotinum Flora of Northern America Plants described in 1803 {{Eupatorieae-stub

References

Further reading

External links