The first vowel of pseedevernia
heard as pseedevernia
spelled pseudevernia
It is oo, and it is spelled eu. Pseudevernia.
What the ear did
The letters eu are a single Greek unit and they never say ee. Anyone who has met pseudonym or pseudoscience has already met this vowel; the lichen name simply loses the o that usually follows it.
P-S-E-U-D-E-V-E-R-N-I-A
The full entry for pseudevernia covers the name itself.