Hi Creakey - it's always nice to post the full clue, number of letters & any you've placed, so that people without the puzzle can also help you - thanks for next time! :-)
That said -
25a Mexican and south-west US spiny shrub with clusters of red flowers (8) - Ocotillo
Thanks OAP60. With equal respect please see http://www.onelook.com/?w=Octilla&ls=a, the entry under Wordnik does call it the Ocotilla Cactus. So maybe the Telgraph compiler "got it wrong". Or at least left scope for confusion!