Flower, one adapted to the desert, to weaken after setback (8)
I believe the answer is:
camellia
'flower' is the definition.
(I've seen this before)
'one adapted to the desert to weaken after setback' is the wordplay.
I cannot really understand how this works, but
'one' could be 'me' (a setter might use 'one' to humourously mean 'me') and 'me' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for camellia that I've seen before include "Claim ale from the flowering shrub" , "Showy evergreen shrub" , "Shrub related to tea plant" , "Shiny-leaved shrub" , "Lima lace (anag) - evergreen shrub" .)