Thread:User talk:CodeCat/*flauhs or *flauhaz

I am not sure whether or not to move Appendix:Proto-Germanic/ to Appendix:Proto-Germanic/. Vladimir Orel 2003 reconstructs this noun as *flauhs, but Kroonen 2013 reconstructs the same word as *flauhaz. How do you explain umlaut in German Floh/Flöhe and Icelandic fló/flær? Is the plural vlooien of Dutch vlo also umlauted or is the /ooi/ pronounced as a true dipthong? (I'm not familiar with dutch orthography). I can neither find any good Middle Saxon nor Middle Dutch dictionaries in English to see if the noun was also umlauted in those languages as well (note the asterisk next to the Old Saxon and Old Dutch entries).