Prothalus or Prothallus: How To spell?

The word Prothalus is misspelled against Prothallus, a noun meaning "The minute primary growth from the spore of ferns and other Pteridophyta, which bears the true sexual organs; the oophoric generation of ferns, etc."

Prothallus has double "ll" is mispronounced as "l"
Remember double 'LL' in between the strings protha & us which should not be misspelled with single 'L'
Wrong Spelling:  protha-l-us 
Correct Spelling:  protha-ll-us 
Check more misspelled words of Prothallus to spell it correct.