Figure 1.

A living Ulva specimen (U. aragoënsis). (A) The developed thallus with sporulation in the upper part. Above the part indicated by the arrow, all the cells formed spores and some of them released spores. Arrowhead indicates a small holdfast; (B) Cross-section of the middle part of the thallus having a two-cell layered structure; (C) Surface view of somatic or blade cells in the vegetative state in the middle part of the thallus; (D) Surface view of the cells forming spores. Arrowheads indicate empty cells after spores were released.