Erechtites hieraciifolius (Pilewort)
|Also known as:
|American Burnweed, Fireweed
|part shade, sun; disturbed soil, along roads, along shores, open woods
|July - September
|2 to 8 feet
|Wetland Indicator Status:
|MN county distribution (click map to enlarge):
|National distribution (click map to enlarge):
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Clusters of bud-like flowers at the top of the stem and the end of branches arising from leaf axils near the top of the plant. Flowers are about a ¼ across and petal-less, with 2 sets of bracts. The inner bracts, often with purplish tips, form a ½-inch tube exposing just the yellowish to creamy white stamens at the top. The base of the tube is swollen with a few short thread-like outer bracts attached at the bottom. Early flowers heads are in a tight cylindrical cluster at the end of the main stem but as the plant matures and side branches proliferate, clusters become more open, with single flowers at the ends of long naked stalks.
Leaves and stem:
Leaves are to 8 inches long and 3 inches wide, crisp and fragile, lower ones are broad lance shaped, tapered to a short stalk, shallow to deeply lobed with jagged teeth around the edges, sparsely hairy on the underside along the midrib, becoming smaller and stalkless or clasping as they ascend the stem. Stems are brittle and erect, round with vertical ridges, smooth or with sparse speading hairs. A single large main stem when young, but forming many upper flowering branches with age.
Fruit is a brown seed with a tuft of bright white hairs to carry it off in the wind. The base of the floral tube swells even more as seed develops, and the inner bracts open up and flare out to release the seed.
Notes:An early pioneer species on disturbed sites, Pilewort shows up often around human habitations. I've seen large populations erupt in wetalnd restoration sites when more dominant species, such as cattails, have been repressed. It seems to have a preference for moist soil but is found in drier habitats as well. Overall, the plant resembles the wild lettuces (Lactuca spp.) but is only distantly related. Flowers of the various lettuce species open up and have numerous ray flowers (petals).
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Photos by K. Chayka taken in Ramsey County. Photos by Peter M. Dziuk taken in Anoka County.
Have you seen this plant in Minnesota, or have any other comments about it?