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Cirsium arvense
A thistle which seemed to have lost its chlorophyll towards the top. This is a result of the bacteria Pseudomonas syringae pv. tagetis, often abbreviated as Pst, which results in any new growth of the thistle becoming white and lacking color pigments. The lack of color can result in death of the plant, or slowed growth.
Found in an old field in Maine. Cirsium arvense is an invasive species.
pv. stands for pathovar, which is a strain of bacteria: http://www.wesleychun.phytobacteria.org/... http://www.ext.colostate.edu/pubs/natres...
Spotted on Aug 16, 2012
Submitted on Dec 14, 2012
5 Comments
Thank you very much for the ID, Chester! This is such a cool example of bacterial parasitism.
I agree with, you Natral, the chemical does appear to do the same as the bacteria!
I found this, http://www.new-ag.msu.edu/Home/tabid/37/...
Hi Natral List! This was taken in a field where absolutely no chemical is sprayed on the field. This thistle was colored naturally this way.
Thanks Chester! I didn't know you could eat them. I thought the needles would hurt, but they must soften when cooked.
I can't help with species, very cool though, I prefer my thistles blanched.