Knapweed, Spurge and Toadflax type Differences

 

Leafy SpurgeLeafy Spurge (Euphorbia esula). Broken stems ooze a sticky white latex sap (don't get this sap in your eye as it can damage eye tissue). The tap root can reach down 30 feet and the seeds project explosively up to 12 feet.

See pages 13, 20-23 in the following FS document for descriptions of other types of spurge. Our insects will also attack Cypress Spurge.

http://www.fs.fed.us/foresthealth/technology/pdfs/LeafySpurgeBiocontrols.pdf

 

dalmation toadflaxDalmatian Toadflax (Linaria dalmatica) has wide waxy leaves and beautiful snapdragon flowers.

 

 

 

 

 

 

 

 

yellow toadflaxYellow toadflax (Linaria vulgaris) has thinner leaves than dalmation, flowers are smaller, but similar.This plant is also known as butter and eggs.

 

 

 

 

 

 

 

photos of spurge, toadflax by USDA APHIS

 

white flowerDiffuse Knapweed has white flowers (very rarely purple) and has sharp tipped bracts (bracts are the scales around the seed head).

 

 

purple flowerSpotted Knapweed has purple flowers (very rarely white). Bracts are not sharp tipped and are fringed in black giving the seed head a spotted appearance. It produces from 5000 to 40,000 seeds annually and can live an average of 3 to 5 years, frequently up to 9.

 

large purple flower

 

Russian Knapweed also has purple flowers. Bracts are not fringed in black and have transparent tips-- go to the following link for several pictures.

http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Acroptilon+repens

 

 

Squarrose knapweed, Brown, Black and Meadow knapweeds all look very similar to Spotted knapweed. For information on telling the differences see pages 15-20 (especially page 17) of:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCcQFjAA&url=http%3A%2F%2Fwww.invasive.org%2Fweeds%2FKnapweedBook.pdf&ei=MKP4VPi8BonwoATJ_4KIBQ&usg=AFQjCNHQyjzPC5fDOMqSMS9aFr0OWqAw2Q&sig2=sejmdX3VCj8u5cyss5YQrw&bvm=bv.87611401,d.cGU

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