Butonweed or Buttonweed: How To spell?
The word Butonweed is misspelled against Buttonweed, a noun meaning "The name of several plants of the genera Spermacoce and Diodia, of the Madder family."
Buttonweed has double "tt" is mispronounced as "t"Remember double 'TT' in between the strings bu & onweed which should not be misspelled with single 'T'
Wrong Spelling:  bu-t-onweed  Correct Spelling:  bu-tt-onweed 
Check more misspelled words of Buttonweed to spell it correct.