One of the flowers from Trim, in a manner of speaking (4)
I believe the answer is:
iris
'the flowers from trim in a manner of speaking' is the definition.
I can't tell whether this definition defines the answer.
'one of' is the wordplay.
'one' becomes 'i' (Roman numeral).
'of' becomes 'ris' (I can't justify this - if you can you should believe this answer much more).
'i'+'ris'='IRIS'
Can you help me to learn more?
(Other definitions for iris that I've seen before include "is 21[WOMAN], perhaps" , "Flower and eye membrane" , "Greek goddess of the rainbow" , "Part of the eye, usually brown or blue" , "Murdoch in writing" .)