Keep endless original artefacts from island in greenhouse (12)
I believe the answer is:
conservatory
'island in greenhouse' is the definition.
'conservatory' can be an answer for 'greenhouse' (conservatory is a kind of greenhouse). I am not certain of the 'island in' bit.
'keep endless original artefacts' is the wordplay.
'keep' becomes 'conserve' (conserving is a kind of keeping).
'endless' means to remove the last letter.
'original artefacts' becomes 'atory' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'conserve' with its last letter removed is 'conserv'.
'conserv'+'atory'='CONSERVATORY'
'from' is the link.
Can you help me to learn more?
(Other definitions for conservatory that I've seen before include "Hothouse" , "Sun lounge" , "school of music" .)