Particular type of black grass (5)
I believe the answer is:
breed
'particular type' is the definition.
'breed' can be an answer for 'type' (thesaurus). I am not sure about the 'particular' bit.
'black grass' is the wordplay.
'black' becomes 'b' (abbreviation as in pencil classifications).
'grass' becomes 'reed' (type of grass plant).
'b'+'reed'='BREED'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for breed that I've seen before include "train" , "Strain; reproduce" , "Special variety of domesticated animal" , "Produce offspring, say horses" , "eg Merino" .)