The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, Spirogyra and stoneworts.
ðə lˈɑːɹdʒɪst ænd mˈoʊst kˈɑːmplɛks mɚɹˈiːn ˈælɡiː ɑːɹ kˈɔːld sˈiːwiːdz, wˌaɪl ðə mˈoʊst kˈɑːmplɛks fɹˈɛʃwɔːɾɚ fˈɔːɹmz ɑːɹ ðə tʃˈæɹəfˌɪɾə, ɐ dᵻvˈɪʒən ʌv ɡɹˈiːn ˈælɡiː wˌɪtʃ ɪŋklˈuːdz, fɔːɹ ɛɡzˈæmpəl, spˌɪɹədʒˈaɪɹə ænd stˈoʊnwoːɹts.