Family Description:
Plants are crusts, filaments or blades. Pit connections (proteinaceous plugs that connect neighboring cells) have not been observed in any member of this family, including a prostrate uniseriate filamentous phase that occurs in the life history of some species and that otherwise resembles the conchocelis of the following order.

Species description:
Seagrass Laver is pinkish red to purple, and develops blades that are up to 5 cm (about 2 in) long. The small, cushion-shaped holdfasts are present throughout the year, and from spring to fall these give rise to up to thirty blades each. The blades are very thin, like those of Porphyra, to which it is somewhat distantly related. They are widest above the middle, and taper to short stalks basally. Each cell contains a single large, stellate chloroplast that has a single pyrenoid.

Seagrass Laver is an epiphyte on surfgrasses (Phyllospadix) and eelgrass (Zostera); it does not occur on rocks. Asexual spores can be released from marginal areas of the blades; these can settle on seagrass blades and germinate to give rise to new cushions, which, in turn, can develop their own blades. Sexual reproduction involves the unequal division of a cell to form a small male gamete and a larger female gamete.

This species was named in honor of Gilbert Morgan Smith, an American phycologist and professor of botany at Stanford University, who made valuable contributions to our knowledge of the algae of California.

Source:  North Pacific Seaweeds

Synonyms and Alternate Names:
Porphyra naiadum