1925] Setchcll-Gardner : MeJaiwphijceae 513 



3. Leathesia amplissima S. and G. 



Plate 43, fig. 64 



Thallus hollow, subglobose to irregular, attached by a broad area, 

 the central part of which disintegrates on nearing maturity, 3-8 cm. 

 diam. ; color yellowish brown ; interior colorless cells relatively large, 

 compact and angular from compression, becoming radially arranged 

 and smaller, toward the surface ; hairs single, scattered over the whole 

 free surface, 11-13//. diam. ; paraphyses clavate, enlarging gradually 

 from the base to the apex, 55-65/1, long, 4— 7/x diam. at the base, 7-12/t 

 at the apex, 4-5 cells long ; chromatophores densely crowded ; zoo- 

 sporangia ovoid to ellipsoidal, 38-46/x long, 22-28/t broad ; gametangia 

 unknown. 



Growing on rocks and over other small algae, in tide pools in the 

 lower littoral and upper sublittoral belts. Central California (Pacific 

 Grove and Monterey). 



Setchell and Gardner, Phyc. Cont., VII, 1924, p. 3. 



Leathesia amplissima is not readily distinguishable in gross mor- 

 phological characters from L. difformis as we understand that species 

 at present. The histological structure, however, is essentially different 

 as may be seen from our descriptions and figures. 



family 7. PUNCTARIACEAE kjellm. 



Fronds from filiform and almost monosiphonous to saccate, ligulate 

 or broadly expanded and membranaceous, attached by a relatively 

 small parenchymatous disk or by rhizoidal filaments, all but the mono- 

 siphonous species differentiated into an inner and an outer tissue, the 

 inner mostly of colorless cells and the outer of color bearing cells; 

 reproduction both asexual, by zoosporangia projecting slightly or not 

 at all beyond the surface, and sexual, by gametangia projecting wholly 

 or in part beyond the surface; both zoosporangia and gametangia 

 transformed single surface cells, either scattered or collected into 

 definite sori ; hairs ( and paraphyses ? ) present in some. 



Kjellman, in Gleerup, Enum. PL Scand., 1880, p. 9 (fide Foslie, 

 Contr. Knowl. Mar. Alg. Norway, I, 1890, p. 98) ; Oltmanns, Morph. 

 und Biol, der Alg., 1922, p. 49 et seq. Punctarieae Thuret, in Le Jolis, 

 Liste alg. mar. Cherb., 1863, p. 14 (in part) ; Farlow, Mar. Alg. New 

 Eng., 1881, p. 63. 



As usually limited, the Punctariaeeae include the genera Omphalo- 

 phyllum Rosenv., Phaeosaccwn Farlow, Punctarki Grev., Desmo- 



