Shown on map, but npc doesn't have a quest available.
https://classic.wowhead.com/quest=3791/the-mystery-of-morrowgrain
The wowhead comments suggests that you can only get this if you have accepted Morrowgrain Research quest from Staghelm in Darnassus.

Questie v4.1.1
Hunter level 47.

Duplicate of #885 , but thanks for your report! :)