After seeing how some areas of the Underrealm looked and after hearing how the Tulnar adapted to their environment I couldn't help but think of this.
There's no confirmation as the most we have about the character creator for the Tulnar is a quote on the wiki as follows:
Players will have dials to adjust the reptilian, mammalian, humanoid, and other attributes of their Tulnar character in the Character Creator.
It could be in the OTHER category but I wouldn't mind if we could get more clarification on the Tulnar character creator in a future Q&A.
If we do get a plant and fungus attribute slider I can talk about what a fun guy I am.