Myxophyceae 273 



496. Schizosiphon obscurus Dickie. Notes on some Algae found in the 



North Atlantic Ocean. Journ. Linn. Soc. Bot. 11: 459. f. 5. 1871. 

 De Toni. Syll. Algar. 5: 633. 1907. 



Plate XVIII. fig. 14. 



Filaments straight, gradually tapering upwards from the large, some- 

 what spherical basal cell (heterocyst?); sheaths distinct, obscurely lamel- 

 lose; trichomes shorter than the sheath, usually torulose throughout. 



West Indies ?. Forming a thin stratum on drift wood. (Mitchell). 

 "The contents of the bottle were collected in the North Atlantic on the 

 Z4th of November, 1867. * * * Considering our position, I concluded 

 that the substance must have come from some part of the American con- 

 tinent or the West Indies within the influence of the Gulf Stream." — Dickie. 



497. Mastigonema paradoxum Kuetzing. Phyc. Gen. 233. pi. 5. f. 3. 1843. 



De Toni. Syll. Algar. 5: 632. 1907. 

 Wolle. Fresh Water Algae. III. Bull. Torr. Bot. Club. 6: 184. 1877. 

 Plate XVIII. fig. IS. 



Filaments somewhat solitary; sheaths wide, colorless or yellowish 

 brown, transparent, homogeneous; trichomes up to 13 mic. in diameter, 

 simple or sometimes branched, often moniliform, flaccid or flexuously 

 curved, long; heterocysts spherical, two to four times shorter than the 

 diameter of the trichome. 



Pennsylvania. On wet sides of wooden water box. (Wolle). 



498. Calothrix rhizosoleniae Lemmermann. Planktonalg. in Ergebn. ein 



Reise n. d. Pacific. 355. 1899. De Toni. Syll. Algar. 5: 630. 1907. 



Lemmermann. Algenfl. Sandwich.-Inseln. Bot. Jahrb. 34: 627. pi. 7. 

 f. 2, 3. 1905. 



Filaments up to 3 mic. in diameter, slightly thickened at the base, 

 slightly tapering at the apex; sheaths transparent, close; trichomes 2.5 mic. 

 in diameter; cells 1.5 mic. in length. 



Hawaii. In plankton on Rhizosolenia and Hemiaulus deli- 

 catulus Lemm. Between Hawaii and Laysan. 1896-1897. (Schauinsland). 



499. Mastigonema sejunctum Wood. Contr. Hist. Fresh-Water Algae 



North America. 53. pi. 4. f. 2. 1872. De Toni. Syll. Algar. 5: 631. 

 1907. 



Plant mass somewhat caespitose, soft, parasitic; filaments unbranched, 

 tapering at the apex; sheaths usually wide and distinct, hyaline, often 

 strongly undulate, the apex mostly much amplified and dissolved into 

 fibrillae; trichomes continuous or more rarely interrupted; cells short or 

 long; cell contents granular, yellowish olive or greenish; heterocysts about 

 equal to the filament in diameter. 



Michigan. In bog growing on edges of minute leaves so as to form 

 little prominences or thickenings of the margin. 



Soc. Mastigothrix turgida Wolle. Fresh Water Algae. III. Bull. Torr. 

 Bot. Club. 6: 184. 1877. De Toni. Syll. Algar. 5: 632. 1907. 



