THE ALG^E 399 



Family STIG ONE MA TA CE^^. 



Hapalosiphon pumilus (Kuetz.) Kirchner. 



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



Stigonema minutum (Ag.) Hassall. 



Forming a thin brown coating with Chroococctis rjifescens on damp 

 rocks several hundred feet above sea level, Prince William Sound 

 (Trelease i^oi). 



The threads are about i mm. high, 13—25 <j. 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, 303). 



The plant forms dark brown, loosely CJEspitose tufts 2-7 or S '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/^) all bearing hormogones ; trichomes 21— 40 /^ broad ; 

 sheath broad, indistinctly lamellose, yellowish brown except near the 

 ends on young branches ; cells 25—35 ,a, shorter tha-n broad, surrounded 

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

 13 /u broad, 50-65 ,a long. 



Y^xx^xXy RiVULARIACEvE. ■ 



Calothrix fusca (Kuetz.) Bornet. 



Imbedded in the gelatinous coating of Batrachospermtun vagum 

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



The plants, which were apparently immature, resemble the form 

 of C. cBriiginosa 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 /a broad. 



Calothrix scopulorum (Weber & Mohr) Ag. 

 In salt water, Puget Sound. 



Rivularia biasoUetiana Menegh. 



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

 Identified by Setchell. 



1 Kuetz. Tab. Phvc. 2 : PI. 45, Figs. 5 and 6. 



