NO. 



2 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 245 



6. Blades solitary, or rarely more than 2 from the attach- 

 ment disc, 15-100 cm. long, 1.5-6 cm. broad; medullary 

 filaments loosely arranged and interlacing .... 



G. schizophylla 



6. Blades several to many from the attachment disc, 10-25 

 cm. long, 0.7-2.5 cm. broad; medullary filaments rather 

 compactly and mostly longitudinally arranged 



G. multiphylla 



7. Branching multifarious 8 



7. Branching dichotomous, flabellate, pinnate, or irregular, but 



distichous rather than multifarious 9 



8. Thalli 8-12 (20) cm, high or more; central medulla very 



loose, often hollow G. filicina 



8. Thalli 2-3 (7) cm. high; medulla never hollow 



G. hancockit 



9. Branching totally irregular; broader thallus parts over 3 mm. 



broad G. abreviata 



9. Branching of uninjured blades normally pinnate; broader 



thallus parts over 3 mm. broad ... (7. prolongata 



9. Branching wholly or partly dichotomous ; broader thallus parts 



under 2.5 mm. broad 10 



10. Broader mature thallus parts variegated; branching in 



part pinnate G. versicolor 



10. Thallus uniformly colored throughout; branching dicho- 



tomo-flabellate G. dactylifera 



11. Thalli smooth except for short, subulate ultimate pinnules 



G. ? johnstonii 



11. Entire thallus beset with short, blunt, branched spines 



G. ? squarrulosa 



Grateloupia maxima (Gardner) Kylin 

 PI. 1, fig. 1 



Kylin 1941, p. 10, fig. 2C; Doty 1947, p. 171. Grateloupia cutleriae 

 forma maxima Gardner (1911), in Collins, Holden & Setchell, P.B.A., 

 fasc. E., no. CXXIV. 



Thalli consisting of a simple, ± lanceolate, membranous blade 1-2.5 

 m. long, 10-30 cm. wide and about 150-200 (250) /x thick, entire or 

 slightly lobed in upper parts, the margins sometimes undulate, cuneate 

 at the base to a very small, discoid attachment less than 2 mm. in dia- 

 meter; cortex rather thin, the anticlinal filaments usually of 3-4 very 



