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Black Swallow-wort, Louise's Swallow-wort
Family: Asclepiadaceae;
Genus: Cynanchum;
Species: louiseae;
Synonyms:
Cynanchum nigrum
Growth Form: Vine
General:
Herbaceous, perennial vine twines 3-8 feet high.
Flowers:
Tiny, dark purple with 5, pointed, downy, triangular petals that are as long as wide.
Fruits and Seeds:
Milkweed-like, slender and tapered, 1 - 3 inches long turn brown when ripe; Seed on silky filaments, wind dispersed. Reproduction primarily by seed; plants may spread by trailing, rooting (stoloniferous) stems.
Leaves:
Dark green, shiny, opposite, 1 - 4 inches long, toothless, narrowly to broadly oval-shaped with pointed tips.
Stems or Branches:
Single, sometimes branching.
Threatens:
Threatens most upland community types including woodlands, forests, grasslands, and savannas; can persist in sun or shade.
Look-Alikes:
Milk & Honey Vine (Blue Vine), Cynanchum leave (Ampelamus albidum); flowers cream or yellowish white, stems and leaves with a milky sap, base of leaf blades heart-shaped.
Distribution:
Native to southwestern Europe: Italy, France, Portugal, and Spain. Has been reportedhas been reported from Maine to Michigan to Nebraska as well as California.
Other Links:
http://www.dnr.state.wi.us/invasives/fact/swallowwort_black.htm
http://www.nps.gov/plants/ALIEN/fact/cylo1.htm
http://tncweeds.ucdavis.edu/esadocs/vincnigr.html
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BSW flower
D. Eagan, University of Wisconsin
BSW vine and pod
D. Eagan, University of Wisconsin
BSW pods
D. Eagan, University of Wisconsin
BSW flowers and vine
D. Eagan, University of Wisconsin
BSW Plant
D. Eagan, University of Wisconsin
BSW flower buds
D. Eagan, University of Wisconsin
BSW flowers and flower buds
D. Eagan, University of Wisconsin
BSW Vine
D. Eagan, University of Wisconsin
BSW Leaves
D. Eagan, University of Wisconsin
BSW Invaded area
D. Eagan, University of Wisconsin
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