“Plants” one sees in the book spelled phonetically (5)
I believe the answer is:
reeds
'plants one' is the definition.
'reeds' can be an answer for 'plants' (I have seen 'Marsh plants ' mean 'reeds' so perhaps 'plants' could also mean 'reeds'). I am unsure of the 'one' bit.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for reeds that I've seen before include "Woodwind instruments" , "Tall slender grasses of wet areas" , "Thin pieces of cane in musical instruments" , "Plants providing thatching material" , "Stems for pens" .)