Spiny desert plants (5)
I believe the answer is:
cacti
'spiny desert plants' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cacti that I've seen before include "Features of westerns" , "growing group" , "Spiky desert plants in plural" , "They store water" , "Spiny succulent plants" .)