Sargasum or Sargassum: How To spell?
The word Sargasum is misspelled against Sargassum, a noun meaning "A genus of algae including the gulf weed."
Sargassum has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings sarga & um which should not be misspelled with single 'S'
Wrong Spelling:  sarga-s-um  Correct Spelling:  sarga-ss-um 
Check more misspelled words of Sargassum to spell it correct.