[399] THE ALG^ 163 



Family STIG ONE MA TA CEy^. 



Hapalosiphon pumilus (Kuetz.) Kirchner. 



In a freshwater pond near Seldovia, Cook Inlet (424). 



Stigonema minutum (Ag.) Hassall. 



Forming a thin brown coating with Chroococcus rufescens on damp 

 rocks several hundred feet above sea level, Prince William Sound 

 (Trelease 501). 



The threads are about i mm. high, 13-25 11 broad, irregularly 

 branched and flexuously curved ; sheath yellowish brown ; internal 

 tegument much darker ; main filament usually of one layer of cells ; 

 the branches usually of two or more ; heterocysts abundant, yellowish, 

 lateral or intercalary. 



Stigonema ocellatum (Dillw.) Thur. 



On rocks in a rapid stream emptying into Glacier Bay ; floating in a 

 quiet freshwater pool. Prince William Sound (300, 302). 



The plant forms dark brown, loosely caespitose tufts 2-7 or 8 mm. 

 high which are attached at first but finally are floating ; irregularly 

 branched, branches elongated, patent, primary filaments one or two cells 

 thick (35-50^1) all bearing hormogones; trichomes 21-40/1 broad; 

 sheath broad, indistinctly lamellose, yellowish brown except near the 

 ends on young branches ; cells 25-35 /z, shorter than broad, surrounded 

 by a dark brown tegument ; heterocysts lateral, scarce ; hormogones 

 13 /i broad, 50-65 [i long. 



Family RIVULARIACE^^. 



Calothrix fusca (Kuetz.) Bornet. 



Imbedded in the gelatinous coating of Batrachospertnum vagum 

 from a freshwater pond, Cook Inlet (423) ; Kadiak Island (504). 



The plants, which were apparently immature, resemble the form 

 of C. ceruginosa of Kuetz. ^ The threads are loosely gregarious, 

 broad, curved and somewhat enlarged at the base; sheath broad, 

 ochraceous with age, produced into long thread-like articulations; 

 heterocysts 10 ix broad. 



Calothrix scopulorum (Weber & Mohr) Ag. 

 In salt water, Puget Sound. 



Rivularia biasolletiana Menegh. 



On rocks in freshwater streams, Juneau (76) ; Glacier Bay (102). 

 Identified by Setchell. 



> Kuetz. Tab. Phyc. 2 : PI. 45, Figs. 5 and 6. 



