Plant collections outside university (5)
I believe the answer is:
lotus
'plant' is the definition.
(lotus is a kind of plant)
'collections outside university' is the wordplay.
'collections' becomes 'lots' (lot is a kind of collection).
'outside' means one lot of letters goes inside another.
'university' becomes 'u'.
'lots' going around 'u' is 'LOTUS'.
(Other definitions for lotus that I've seen before include "Mythical fruit inducing dreamy state" , "Cross-legged position adopted in yoga" , "British sports and racing car manufacturer" , "Sacred waterlily" , "Flower causing forgetfulness - cross-legged position" .)