The only groups to exhibit three-dimensional multicellular thalli are the reds and browns, and some chlorophytes.
ðɪ ˈoʊnli ɡɹˈuːps tʊ ɛɡzˈɪbɪt θɹˈiːdᵻmˈɛnʃənəl mˌʌltɪsˈɛljʊlɚ θˈæli ɑːɹ ðə ɹˈɛdz ænd bɹˈaʊnz, ænd sˌʌm klˌoːɹoʊfˈaɪts.