Milky sap of rubber trees (5)

I believe the answer is:

latex

(Other definitions for latex that I've seen before include "Milky substance from rubber tree" , "Milky fluid produced by plants" , "Whitish milky fluid" , "Tree fluid used to make rubber" , "Milky fluid from poppies, rubber plants etc" .)

I've seen this clue in The Telegraph.

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