Cultivated hemp plant, name not shown in brochure (8)
I believe the answer is:
pamphlet
'brochure' is the definition.
('pamphlet' can be a synonym of 'brochure')
'cultivated hemp plant name not' is the wordplay.
'cultivated' is an anagram indicator.
'name' becomes 'n' (common abbreviation e.g. on forms).
'not' indicates named letters should be taken away.
'hemp'+'plant'='hempplant'
'hempplant' with 'n' taken out is 'hempplat'.
'hempplat' is an anagram of 'PAMPHLET'.
'shown in' acts as a link.
(Other definitions for pamphlet that I've seen before include "'Booklet, leaflet (8)'" , "Leaflet containing information" , "Small booklet or leaflet" , "Tract" , "Small booklet of information" .)