One very good English plant coming up, one with hollow leaves (7)

I believe the answer is:

isoetes

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

'one very good english plant' is the definition.
The answer and definition can be both plants as well as being singular nouns.
Perhaps you can see a link between them that I can't see?

I don't understand the rest of the clue.

Can you help me to learn more?

(Another definition for isoetes that I've seen is " Quillwort".)

I've seen this clue in The Times and The Sunday Times.

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.