Philanemo Mushroom is found under the eaves of houses.
You can purchase Philanemo Mushrooms from Botanist Chloris. The refreshes every 3 days and the items don't change. oou can't see her at night.
Mondstadt Region Puzzles, Secrets, and Hidden Chests
Puzzles, Secrets, and Hidden Chests in Dragonspine
How to Beat Monsters/Farm Enemy Drops
Crystal Core Farm Locations
Xiao & Invitation to Mundane Life Event Wish
Ganyu Event & Adrift in the Harbor Wish
Top Mining Spots in Dragonspine