Complex sentence: Gametangial and tetrasporangial plants are not known Maggs, C.A. and Hommersand, M.H. Seaweeds of the British Isles.
Split into simpler sentences: Gametangial and tetrasporangial plants are not known. Reproduction is by specialized propagules Maggs, C.A. and Hommersand, M.H. Seaweeds of the British Isles.