The vowel before -nia in cladania
heard as cladania
spelled cladonia
Cladonia. The vowel before -nia is o.
What the ear did
It sits directly after the stressed syllable and gets almost no time in speech. The o is the last letter of klados, still doing its job inside the Latinised name.
C-L-A-D-O-N-I-A
The full entry for cladonia covers the name itself.