Ulva rigida

Ulva rigida C. Agardh

Ulva rigida C. Agardh, 1823:410; Howe, 1914:18; Setchell and Gardner, 1920b:269; Setchell and Gardner, 1924a:717; Setchell and Gardner, 1930:137; Levring, 1941:606; Dawson, 1944:202; Smith, 1944:47; Dawson, 1949:239, 242; Taylor, 1947:60; Papenfuss, 1960:305, text-fig. 4, pl. 1: fig. 11; Dawson, 1961b:374; Dawson et al., 1964:8; Dawson, 1966a:5; Scagel, 1966:61, pl. 30: figs. A–C, pl. 31: figs. A–H; Bliding, 1968:546, figs. 6–10; Acleto O., 1973:9; Abbott and Hollenberg, 1976:87, fig. 41; Huerta-Múzquiz, 1978:338; Koeman and van den Hoek, 1981:37, figs. 78–107; Littler and Littler, 1981:151–153; Hoeksema and van den Hoek, 1983:74, figs. 20–24; Littler and Littler, 1984:15, 24; Mendoza-González and Mateo-Cid, 1985:22; L. Aguilar-Rosas and Pacheco-Ruíz, 1986:77; Dungan, 1986:295; Phillips, 1988:445, figs. 24–26; Santelices, 1989:243, pl. AA: fig. 5; R. Aguilar-Rosas and Machado-Galindo, 1990:188; R. Aguilar-Rosas et al., 1990:123; Stewart, 1991:28; Mateo-Cid and Mendoza-González, 1991:27; Rocha-Ramírez and

Siqueiros-Beltrones, 1991:30; R. Aguilar-Rosas and M. Aguilar-Rosas, 1994:517, 526; Mateo-Cid and Mendoza-González, 1994b:44; González-González et al., 1996:290; Hoffmann and Santelices, 1997:68, fig. 11; Mendoza-González and Mateo-Cid, 1998:25; Mendoza-González et al., 1999:60; L. Aguilar-Rosas et al., 2000:133; Kraft, 2000:532, fig. 11A–E; Cruz-Ayala et al., 2001:190; Abbott and Huisman, 2004:57, fig. 12A–D; Hayden and Waaland, 2004:379, tbl. 3; Pedroche et al., 2005:32; Mateo-Cid et al., 2006:48; Kraft, 2007:46, fig. 19A–E; Pacheco-Ruíz et al., 2008:191, 201.

Ulva lactuca var. rigida (C. Agardh) Le Jolis, 1863:38; Collins, 1903:8, pl. 41: fig.1; Collins, 1909b:215; Howe, 1911:490; Huerta-Múzquiz, 1978:335; Huerta-Múzquiz and Mendoza-González, 1985:42; Pacheco-Ruíz and Zertuche-González, 1996a:432.

Blades broader than tall, up to 5 cm tall and to 10 cm wide in the Gulf, dark green; sometimes deeply lobed, usually with dentate margins (spines 1–3 cells long); firm and comparatively stiff, narrowed abruptly at base to a short solid stipe above a small discoid holdfast. Cells in surface view irregularly arranged, polygonal to rounded, 10–15 µm in diameter; with a single chloroplast and 1–3 pyrenoids. Transection of 2-cell-layer blade, up to 100 µm thick (thickest in lowermost portion), with a distinct thick hyaline, mucilage layer between cell layers. Cells in transection predominately elongated (most evident in mid to lower portions), occasionally squarish, 15–45 µm tall by 10–15 µm wide.

HABITAT. On rocks, usually exposed; high to low intertidal.

DISTRIBUTION. Gulf of California: Puerto Peñasco to Bahía La Paz. Pacific coast: Alaska to Colima; Peru; Chile; Juan Fernandez Island; Hawaiian Islands.

TYPE LOCALITY. Cádiz, southern Spain (Papenfuss, 1960).