The Hanks & Hodges book on first names gives Clarrie as the English diminutive of
Clara.
This seems to tie in with a 60-odd neighbour's insistence that the proper pronunciation of
Clara is neither clair-uh or clah-ruh but CLAR-uh, i.e. with the first syllable like the first syllable of
Clarence or rhyming with that of
Marion.
I don't like that pronunciation but wonder whether anyone here agrees with my neighbour or has ever heard
Clara pronounced like that.