Plants in cars unexpectedly found by second one (8)
I believe the answer is:
narcissi
'plants' is the definition.
The answer is an example.
'in cars unexpectedly found by second one' is the wordplay.
'unexpectedly' indicates an anagram.
'found by' says to put letters next to each other.
'second' becomes 's' (common abbreviation).
'one' becomes 'i' (Roman numeral).
'in'+'cars'='incars'
'incars' with letters rearranged gives 'narcis'.
'narcis'+'s'+'i'='NARCISSI'
(Other definitions for narcissi that I've seen before include "Flowers including daffodils and jonquils" , "Plants that include the daffodil" , "Flowers named after Greek youth in love with his own appearance" , "Two-toned daffodils" , "Bulbous plants with yellow or white flowers" .)