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Photo: Eupatorium fistulosum

Eupatorium fistulosum Barratt

Hollow Joe-pye Weed

Habitat: Roadsides, moist ditches. [Open wetland, not coastal nor rivershore (non-forested, wetland); Old field / roadside (non-forested, wetland or upland)]

Range: Southern Maine to Iowa, south to Florida and Texas.

Aids to Identification: This Joe-pye weed is characterized by the hollow central cavity of the stem. The stem is also covered with a whitish bloom, and is usually purplish. The whorled leaves grow in groups of 4 to 7, with more rounded teeth than other similar species. There are 4-7 bright pink-purple flowers in each capitulum (flowerhead). The similar species E. purpureum has sharper, more coarse teeth on the leaves.

Photo: Eupatorium fistulosum stem

Ecological characteristics: Known in Maine to occur in moist roadside ditches and stream shores.

Phenology: Flowers July - September.

Family: Asteraceae

Synonyms: Known as Eupatoriadelphus fistulosus (Barratt) King & H.E. Robins.

Known Distribution in Maine: This rare plant has been documented from a total of 9 town(s) in the following county(ies): York.

Dates of documented observations are: 1989 (5), 1993 (2), 1994, 1995, 1996 (3), 1998, 2000, 2001 (3)

Photo: Eupatorium fistulosum flowers

Reason(s) for rarity: At northern limit of range.

Conservation considerations: This plant occurs in small wetlands or moist pockets along roadsides in extreme southern Maine. Some road maintenance is obviously compatible with the species, but populations could be vulnerable to road-widening or extensive shoulder work.