Prenanthes alba (White Rattlesnake-root)
|Also known as:||White Lettuce, Lion's-foot|
|Life cycle:||biennial, perennial|
|Habitat:||part shade, shade; rich woods, thickets|
|Bloom season:||August - September|
|Plant height:||1 to 5 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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Flowers hang down on branching racemes that arise from the leaf axils in the upper half of the plant. Individual flowers are about ½ across with 8 to 14 rays (petals) that have small notches at the tip. The styles are longer than the rays and have divided, curved tips; stamens are hidden inside the tube. There are 2 layers of bracts. The outer bracts are short and green. There are 7 or 8 dull pink to purplish inner bracts forming a tube about ½ inch long. Bracts are hairless except for minute hairs around the edges. When fully open the flower is bell-shaped.
Leaves and stem:
Leaves are highly variable in shape, largest at the base of the plant and becoming smaller as they ascend the stem. Near the base of the plant they are up to 8 inches long and 10 inches wide and often lobed in 3 to 5 parts. As they ascend the stem the shape usually becomes more triangular, diamond shaped, or oval. All leaves are smooth textured, mostly irregularly toothed and have stalks shorter than the leaf blade. Attachment is alternate. Stems are erect, smooth, unbranched except in the flowers, and often purplish or purple spotted.
White Rattlesnake-root is one of the few flowering plants seen in the woods towards the end of summer. It can also be found in smaller forms, typically with smaller, less variable leaves, in rock outcrops and on the rocky shore of Lake Superior. The flower shape is similar to other Prenanthes species, but P. alba is distinguished by its branching clusters of dangling white to pinkish flowers with hairless, purplish bracts, smooth stem and (typically) variable leaf shapes. In some references, P. alba is known by synonym Nabalus albus.
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- White Rattlesnake-root in woodland habitat
- White Rattlesnake-root plant in rocky habitat
- more flowers
- lower leaf variation
- lower leaf variation
Photos by K. Chayka taken at Long Lake Regional Park, Ramsey County, and Crosby Manitou State Park, Lake County.
Have you seen this plant in Minnesota, or have any other comments about it?