Des Higgins wrote:

Senecio as senekio I cannot get used to though so I say seneesio
which I am sure is wrong.

Why would you put the sound 'ee' there? Because you're almost right
with senesio. It's latin, not greek. 'Cio' is not 'kio' in latin, but
'sio'. But then you could just say Ragwort )