Asclepias stenophylla (Narrow-leaved Milkweed)
|Also known as:||Slimleaf Milkweed|
|Habitat:||sun; dry hill prairies|
|Bloom season:||June - August|
|Plant height:||1 to 2 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Round clusters of 10 to 15 flowers each arise from leaf axils in the upper part of the plant. Individual flowers are about ¼ inch long, pale greenish white with 5 flaring petals and a 5-parted crown. The horns are mostly absent, or barely longer than the hoods in the crown.
Leaves and stem:
Leaves are 2 to 6 inches long and very narrow, less than ¼ inch wide, typically folded lengthwise, with little or no leaf stalk and tapering to a fine point at the tip. Attachment is mostly alternate, nearly opposite, and widely spaced. The main stem is green to purplish and unbranched. Stems and leaves are hairless to slightly hairy.
The most spidery of Minnesota's native milkweeds it could be more difficult to spot but for its austere habitat preference. Few-flowered umbels and long thread-like leaves present a delicate profile. A difficult task to find but for direct info on Minnesota's only known location—we walked right up to them. The steepness of the goat prairie and other attending flora in bloom, along with the breath-taking drop of the horizon into verdant valleys below, made for a spectabulus day. According to the DNR, the one known population of Narrow-leaved Milkweed in MN may have migrated here from natural species dispersion, rather than a remnant population from times past. It was added to the State Endangered List in 1984.
Narrow-leaved Milkweed somewhat resembles Green Milkweed (Asclepias viridiflora), which can also have linear leaves but they are broader and its flowers are more green to purple-tinged, with petals that do not flare much if at all.
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Photos by K. Chayka and Peter M. Dziuk taken in Houston County.
Have you seen this plant in Minnesota, or have any other comments about it?