Plant in area captured by company of Roman soldiers (8)

I believe the answer is:

centaury

I'm a little stuck... Click here to teach me more about this clue!

'plant' is the definition.
(centaury is a kind of plant)

I cannot understand how the remainder of the clue works.

(Other definitions for centaury that I've seen before include "Pink-flowered plant of gentian family" , "flowering plant" .)

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.