Collect 1 Underbulk Fungal Sample(s) 0/1 (Paludal Depths)
Head to Paludal Depths, and kill royal guardians (as indicated by on the map), and loot a Sample
This dropped from the Infested Burrowers which where next to the big mushroom where the next drop comes from...
Collect 1 Shik`Nar Fungal Sample(s) 0/1 (Paludal Depths)
Kill dead eyed Shik`Nar and loot a Sample, found in the Northern section of the zone
Not sure if it drops where 3 is since I didn't bother to go there.
The big mushroom pulses every 20s something that breaks invis and puts you in combat so be careful.