Neoralfsia hancockii

Ralfsia hancockii E. Y. Dawson

Ralfsia hancockii E. Y. Dawson, 1944:223, pl. 31: figs. 6, 7, pl. 54: fig. 2; Dawson, 1954a:3; Dawson, 1961b:387; León-Álvarez and González-González, 1993:461, 464; León-Álvarez and González-González, 1995:358, figs. 3, 4; González-González et al., 1996:158; L. Aguilar-Rosas et al., 2000:132; Mateo-Cid et al., 2000a:67; León-Álvarez and González-González, 2003:614, figs. 2–12; López et al., 2004:10; Mateo-Cid et al., 2006:49, 57; Servière-Zaragoza et al., 2007:8; Pedroche et al., 2008:29.

Ralfsia expansa sensu Børgesen 1912a:123; Børgesen 1914:189 (see: León-Álvarez and González-González 2003:614);.Chávez 1972:268; Tanaka and Chihara, 1980b:231, figs. 1B, 2C,D; González-González, 1993:443; León-Tejera et al., 1993:200 [non Ralfsia expansa (J. Agardh) J. Agardh, 1848:63].

Crusts light-brown to reddish brown, orbicular, up to 7 cm in diameter, upper surface smooth with radial and concentric growth lines or rugose to verrucose and with a conspicuous margin; vegetative portions108–306 µm thick; reproductive portions 198–360 µm thick. Crusts firmly attached to substratum by rhizoids. Growth mainly unilateral; in thick portions, filaments may grow downward, tending toward bilateral symmetry. Base of 2–4 horizontal layers of thick-walled, elongate basal cells, 24–42 µm long and 10.5–15.0 µm in diameter; curving upward. Upper layer of assurgent, branching rows of cells; middle cells 22–31.5 µm long by 10.5–18 µm in diameter; outer cells of 4–7 layers of anticlinal cells, 6–10 µm long by 6–8.5 µm in diameter.

Unilocular sporangia, in sori sparsely scattered over thallus surface; ovoid, ellipsoid to clavate, 62.5–93 µm in length and 22–43 µm in diameter; terminal on a narrow stalk of 4–5 cells, 7.5–13 µm in diameter. Paraphyses slender of 10–18 cells, 100–150 µm long; basal cells 9–18 µm long by 3.8 µm in diameter; upper cells 6–12 µm long by 6–8 µm in diameter. Plurilocular sporangia not known for northern Gulf specimens.

HABITAT. Mid intertidal; on rocks and in tide pools; forming small continuous or isolated patches and often associated with crustose coralline algae.

DISTRIBUTION. Gulf of California: San Felipe to Puertecitos; Punta Arena to San José del Cabo. Pacific coast: Isla San Benedicto (Islas Revillagigedo); Nayarit to Oaxaca; Japan.

TYPE LOCALITY. Southern end of San José del Cabo, Baja California Sur.