Hydroclathrus clathratus

Hydroclathrus clathratus (C. Agardh) M. Howe

Encoelium clathratum C. Agardh, 1823:412.

Hydroclathrus clathratus (C. Agardh) M. Howe, 1920:590; Setchell and Gardner, 1924a:727; Setchell and Gardner, 1925:543; Dawson, 1944:324; Dawson, 1959a:19; Dawson, 1961b:395; Dawson, 1962b:197–198, figs. 74, 229; Abbott and Hollenberg, 1976:206, fig.170; L. Aguilar-Rosas, 1982:30, 31; Stewart and Stewart, 1984:141; Huerta-Múzquiz and Mendoza-González, 1985:46; Mendoza-González and Mateo-Cid, 1985:24; Mendoza-González and Mateo-Cid, 1986:421; Sánchez-Rodríguez et al., 1989:40; R. Aguilar-Rosas et al., 1990:123; Oates and Cole, 1990a:12–16; Stewart, 1991:46; Rocha-Ramírez and Siqueiros-Beltrones, 1991:32; Martínez-Lozano et al., 1991:23; Mateo-Cid et al., 1993:50; González-González et al., 1996:297; Pacheco-Ruíz and Zertuche-González, 1996b:171; Kogame, 1997b:228, figs. 7–14; Yoshida, 1998:306; Cruz-Ayala et al., 2001:190; Kraft and Abbott, 2003:246, figs. 2–11; Abbott and Huisman, 2004:183, fig. 68C,D;

R. Aguilar-Rosas et al., 2005b:34; Pacheco-Ruíz et al., 2008:204; Pedroche et al., 2008:70.

Hydroclathrus cancellatus Bory de Saint-Vincent, 1825:419; Setchell and Gardner, 1924a:727.

Algae netlike, initially more or less globose, then becoming irregularly shaped and convoluted with numerous irregularly shaped, variously sized holes; often torn into sheets; somewhat coarse and slippery; attached by groups of rhizoids along the lower surface. Surface perforations from less than 1 mm in diameter to holes over 3 cm in width; larger holes often with inrolled margins; surface distance between the perforations usually less than 2 mm. Colorless hairs in clusters of 3–15 within shallow pits, scattered over and extended above thallus surface. Thallus thickness from less than 200 µm to over 900 µm. Medulla of up to 6 layers of thin-walled, subspherical to ovoid colorless medullary cells, 60–320 µm, around hollow center. Cortex of 1–2 layers of pigmented cells, 6–7.5 µm by 7–17 µm; surface layer in transection papillate, of domed cells, 10–15(–20) µm tall.

Plurilocular sporangia 5–7 µm by 10–12(–25) µm, in 2–3 rows of 3–4 locules; in irregularly shaped sori, usually near hair tufts. Sori scattered and grow separately, spread and coalesce, sometimes covering much of the surface.

HABITAT. On rocks or occasionally epiphytic or entangled on other algae; mid intertidal to shallow subtidal.

DISTRIBUTION. Gulf of California: Punta Perla, northeast end of Isla Tiburón to Bahía de Los Ángeles; Bahía Concepción to Bahía de La Paz. Pacific coast: southern California to Laguna Ojo de Liebre (Scammon’s Lagoon), Baja California Sur; Ecuador; Chile; Hawaiian Islands; China; Japan; Vietnam.

TYPE LOCALITY. “Uncertain” (see Silva et al., 1996a:631). Lectotype with locality of Belle-Île, Brittany, France, was selected by Howe (1920); however, neither Hydroclathrus clathratus or mollusk shells found with the lectotype collection are known from this locality (Hamel, 1937; Silva et al., 1996a; Kraft and Abbott, 2003). Other syntype locales of the basionym, Encoelium clathratum C. Agardh (1823), were Rauki, Waigeo Island, Moluccas, Indonesia; and Shark Bay, Western Australia.