FIGURES 13–14. L. sejunctum. 13 in Systematic survey of Lithothamnion, Melobesia and Mesophyllum species (Hapalidiaceae, Corallinales, Rhodophyta) recorded along the Atlantic coast of Mexico

FIGURES 13–14. L. sejunctum. 13) Section through mature tetrasporangial conceptacle with tetrasporangium (arrow). 14) Pore canal lined by elongated-shape cells (arrow). FIGURES 15–18: Melobesia membranacea, Vigia Chico, Ascension Bay (ENCB 19327). 15) Superficial view of a multiporate conceptacle. The elevated conceptacles belong to Pneophyllum sp. 16) Section through the thallus showing a monostromatic crust. 17) Section through tetrasporangial conceptacle showing sporangia with zonately arranged spores (arrow). 18) Section through the thallus showing 4-5 layers of cells near the conceptacle.