'stalk-associated' originates from Modern English compounding of the noun 'stalk' and the adjective/participle 'associated'.

'associated' comes from Latin 'associare' (ad- + sociare 'to join, unite') via Old French 'associer' and Middle English 'associaten'/'associate'; 'stalk' comes from Old English 'stealc' (related to Proto-Germanic '*stalkaz') meaning 'stem' or 'stalk'.

Individually, 'stalk' originally meant 'stem' and 'associate' meant 'to join or be connected with'; combined as a modern compound the phrase now specifically denotes something connected with or situated on the plant's stalk.