Regurgitated Lichen  

 

they are ground spawns and mobs are in the Northern center most area on the map

they do drop from the Cliknar mobs
drop rate ( i got about 1 drop every 5 mobs)

i counted 11 Ground spawn locations in that one area
Respawn time on the Ground spawn Regurgitated Lichen are about 12 mins
if you are looking for the 7 needed for the mission, just invis up and get the ground spawns there are plenty

( The only see invis might be the named Cliknar Ranger in that area if it is up)


Hope this helps