84 COLLINS AND HERVEY. 



Generally characterized by the slenderness and delicacy of all the 

 parts; typical S. Filipendula, stouter and shorter, with broader and 

 more dentate leaves and more condensed fructification, has not been 

 found here. 



7. S. HYSTRIX J. G. Agardh, 1847, p. 7; 1889, p. 91, PI. VI. Stem 

 terete, smooth; leaves thickish, lanceolate or ovate-lanceolate, entire 

 or obscurely dentate, 3-6 cm. long, 4-8 mm. wide, midrib rather 

 indistinct, no cryptostomata; vesicles spherical, up to 7 mm. diam., 

 pedicel short, sometimes imperceptible; fructification in dense glom- 

 erules of short, verrucose branches; receptacles, vesicles and leaves 

 densely packed along the little branched axis. Harris Bay, Dec., 

 attached, Hervey; washed ashore on Agar's and Bethel's Islands 

 after a storm, Dec., Collins. Apparently recently torn from its 

 attachment. 



While our plant appears to agree in all other respects with S. Hystrix, 

 the receptacles, though quite verrucose, show no spines or teeth. 

 We should hardly have ventured to give it this name, but for what is 

 said by Reinbold in W r eber, 1913, as to sexual dimorphism in Sar- 

 gassum, with presence or absence of spines on the receptacles accord- 

 ing to sex. We suspect that another instance of dimorphism may be 

 found in S. plaiycarpum Montagne and S. vulcjare Agardh, at least 

 the plant distributed under the latter name as P. B.-A., No. 178. 

 We have seen a large number of plants from Florida, some with smooth, 

 some with spiny receptacles, otherwise indistinguishable. 



8. S. PLATYCARPUM Montagne var. BERMUDENSE Grunow, 1915, 

 p. 389. We have not seen this, and include it only on the authority 

 of Grunow. 



FAMILY DICTYOTACEAE. 

 SPATOGLOSSUM Kiitzing. 



S. SCHROEDERI (Mert.) J. G. Agardh, 1880, p. 113, in part; 1894, 

 p. 38; P. B.-A., No. 2027; S. Areschougii Vickers. 1905, p. 58; 1908, 

 part II, p. 38, PI. XI; Ulva Schroederi Mertens in Martius, 1826, p. 21 ; 

 1827, PL II, fig. 3; Taonia Schroederi Farlow in Alg. Am.-Bor. Exsicc., 

 No. 159. Gravelly Bay, Feb., March, Hervey; Gravelly Bay, April, 

 Aug., Cooper's Island, Aug., Collins. Observed only at these two 

 stations, and apparently not common. In the water it shows a bril- 

 liant iridescence. Tetraspores, much like those of Didyota, were 

 found on a few plants; there does not seem to have been any previous 



