276 FRESH-WATER ALG^E OF THE UNITED STATES. 



Plate CXCVI, figs. 2, 3, 4, three filaments 5 branches often 

 very much longer than illustrated, and thinner than the 

 the stem : cells of stem usually more moniliform than those of 



7 



the branchlets ; heterocysts somewhat oval, scattered ; fig. 5, 

 short section of a filament, cells dividing, enlarging, devel- 

 oping large encysted cells, fig. 6 ; from these come Chroo- 

 coccm, figs. 7, 8 ; Palmagloea cells, figs. 9, 10 ; Nostockopsis, 

 Wood, figs. 11-15 5 Nostocs, figs. 16, 17 ; Hormosiphon, fig. 18. 

 Fig. 19, a specimen developing secondary branchlets. 



HAPALOSIPHON BYSSOIDEUS (Hass.) Kirch. 



Stratum turfy, dull black, somewhat olive green ; fila- 

 ments or branchlets ascending ; ^sewdo-branchlets rather 

 short, rigid. Cells primarily as long as wide, later one-third 

 or one-fourth as long, aeruginous or w r ith age brown ; sheath 

 thick, often distinctly lamellate, smooth, ends slightly atten- 

 uate, apices rounded, colorless or golden yellow. Hetero- 

 cysts compressed oval usually between the cells of the stem 

 only ; light yellow. 



Diameter of filaments, 20-25 /* branches somewhat thinner. 



Syn. Hassallia byssoidea, Hass. ; 8irosiphon truncicola, Bab. 



On the trunks of trees, South Carolina and other Southern 

 States. 



Plate CXCV, figs. 10, 11, 12, two younger and two more 

 advanced, branching filaments. 



From trunks of trees near Aiken, South Carolina. 



HAPALOSIPHON TORTJLOSUS, (Bab. ) Kirch. 



Filaments apt to be solitary, rarely longer than 4 mm; 

 sparsely branched ; cells ordinarily half as long as wide, 

 torulose, pale aeruginous ; sheaths close and thin, indis- 

 tinctly lamellate, smooth, brown yellow. 



Diameter of filaments, 22-27 ^ ; branchlets somewhat less. 



On moist rocks intermingled with Gloeocapsa cells, Kirch. 

 From moist rocks, Prince Edward Island, Virginia. The 

 specimen received did not indicate the presence of Gloeo- 

 capsa noted by Kirchner. Their presence would imply a 

 relation to Sirosiphon as originally placed by Rabenhorst ; 

 the arrangement of the branchlets, however, is Hapalosi- 

 phon-like. 



Plate CXCV, figs. 13, 14, a short section of a filament. 



HAPALOSIPHON BREBISSONII. Kg. 



Caespitose, 3-4 lines long, dull aeruginous, much branched, 

 distinctly articulate, articles equal or somewhat longer than 



