This plant has suddenly grown in my garden, and I am not sure whether I should keep it. Could anybody tell me what it is?

I would say Sonchus, there's six species in Turkey. Now all we need to do is find them.

http://www.ncbi.nlm.nih.gov/pu...

Sonchus oleraceus seems to be a common wheat crop invader in Turkey. It's a wide spread species, leaves can vary, they are not prickly and have a milky sap if the stem is broken. Common name Sowthistle.

When you get flower buds it will help. A few species in Europe ...

http://flora.nhm-wien.ac.at/Se...

http://luirig.altervista.org/f...

I found Wildflowers of Turkey!

http://yabanicicek.com/sonchus...

Sonchus asper is the only other on the site, it is prickly. I have both species.

https://www.google.co.uk/searc...

http://yabanicicek.com/sonchus...

http://www.cabi.org/isc/datash...

It's edible.

https://books.google.co.uk/boo...

Yes, it looks to be a variety of sonchus, even though the leaves don't exactly match any of the varieties I have seen so far.

The two mentioned are the most common.

On the google books link it mentions Sonchus oleraceus has a slender spine that is long and hairy.

I can see something on the spine which looks black.



We don't know which species the other 3 are, (Sonchus erzincanicus is in one location only and rare).

https://thefloatingtroubadour....

Keys to some on efloras ..

http://www.efloras.org/florata...

Sonchus tenerrimus and S. palustris could be two more ..

http://www.revolvy.com/main/in...