Plant a bulb with no end of soil (6)

I believe the answer is:

agaric

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

I cannot understand how the rest of the clue works.

(Other definitions for agaric that I've seen before include "Type of mushroom" , "Fungus, eg, mushroom" , "Fungus of mushroom family" , "fungal growth" .)

I've seen this clue in The Telegraph.

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