Helianthus strumosus (Woodland Sunflower)
|Also known as:
|part shade, sun; open woods, woodland edges, roadsides
|July - September
|2 to 6 feet
|Wetland Indicator Status:
|GP: FACU MW: FACU NCNE: FACU
|MN county distribution (click map to enlarge):
|National distribution (click map to enlarge):
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The bracts behind the flower are relatively short, not much exceeding the center disk, and slightly spreading. Width is variable, more often relatively wide but may be narrow. Edges are usually hairy, surfaces are smooth or variously covered in short, stiff hairs. Flowering stems are typically rough textured.
Leaves and stems:
Leaves are 2½ to 7 inches long, ¾ to 4 inches wide, rounded or slightly tapering at the base, usually with a long taper to a pointed tip but lower leaves may be more egg-shaped. Leaf stalks are 3/8 to 1¼ inches long, leaf edges are toothless or with irregular, shallow teeth, surfaces are variously smooth to hairy, often rough textured on the upper surface and densely short-hairy and paler in color on the underside. Attachment is mostly opposite but may be alternate in the upper plant.
The center disk forms a head of dry seed, each seed about ¼ inch long and without a tuft of hair, but with 2 bristly scales at the tip.
Woodland Sunflower is a rather variable species, particularly in leaf shape and degree of hairiness. The few things all the references seem to agree on, and that can actually help distinguish this from other Minnesota native sunflowers, are: a mostly smooth stem that may have a whitish bloom, leaf stalks usually at least ½ inch long, and bracts that do not much exceed the width of the flower disk. Woodland Sunflower most closely resembles Hairy Sunflower (Helianthus hirsutus), which has a bristly hairy stem all the way to the base of the plant, and leaf stalks less than ½ inch long. Woodland Sunflower hybridizes with both Hairy Sunflower and Jerusalem Artichoke (Helianthus tuberosus), which makes an ID even more challenging.
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- Woodland Sunflower plant
- Woodland Sunflower habitat
- leaf hairs
- upper and lower leaf color
- narrow variation of bracts
Photos by K. Chayka and Peter M. Dziuk taken at Sucker Lake, Ramsey County.
Have you seen this plant in Minnesota, or have any other comments about it?