Biterroot or Bitterroot: How To spell?
The word Biterroot is misspelled against Bitterroot, a noun meaning "A plant (Lewisia rediviva) allied to the purslane, but with fleshy, farinaceous roots, growing in the mountains of Idaho, Montana, etc. It gives the name to the Bitter Root mountains and river. The Indians call both the plant and the river Spaet'lum."
Bitterroot has double "tt" is mispronounced as "t"Remember double 'TT' in between the strings bi & erroot which should not be misspelled with single 'T'
Wrong Spelling:  bi-t-erroot  Correct Spelling:  bi-tt-erroot 
Find more incorrect spellings of Bitterroot to spell right way.