''Eupatorium hyssopifolium'', also known as hyssopleaf thoroughwort, is a fall-blooming herbaceous plant native to North America. Like other members of the genus '' Eupatorium'' it has inflorescences containing a large number of very small

flower heads A pseudanthium (Greek for "false flower"; ) 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, compos ...

, each with 5 white disc florets but no ray florets. At 0.5 to one meter (20-40 inches) tall, it is towards the shorter end of the range of heights found in ''Eupatorium'' species. Plants which are classified as ''E. hyssopifolium'' can be either

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

or polyploid, and some of them seem to have been the result of past hybridizations with '' Eupatorium serotinum''. Hybrids with '' E. album'' and '' E. linearifolium'' also seem to exist. The hybrid '' E. torreyanum'' is similar to ''E. hyssopifolium'' but is a hybrid of ''E. serotinum'' and ''

Eupatorium mohrii ''Eupatorium mohrii'', commonly called Mohr's thoroughwort, is a herbaceous perennial plant in the family Asteraceae native to the southeastern and south-central states of the United States, in the coastal plain from Virginia to Texas. It has ...

''. ''Eupatorium hyssopifolium'' is found in much of the eastern and south-central United States, from Massachusetts west to Wisconsin, and as far south as Texas and Florida. It grows in moist soils. ;Varieties *''Eupatorium hyssopifolium'' var. ''hyssopifolium'' - leaves 2–5 mm wide *''Eupatorium hyssopifolium'' var. ''laciniatum'' A.Gray - leaves 5–15 mm wide

Uses

''Eupatorium hyssopifolium'' can be used medicinally (applied externally for insect and reptile bites). It can also be planted near crops to attract beneficial insects.

References

External links

* hyssopifolium Flora of the United States Plants described in 1753 Taxa named by Carl Linnaeus {{Eupatorieae-stub