240 Minnesota Algae 



Water," Castleton, Jamaica. April 1893. (Humphrey). Hawaii. Adhering 

 to leaves, in stagnant water. Mauna Kea, Hawaii. (Berggren). 



Var. tenuissimus (Grunow) Collins and Setchell. Phyc. Bor.-Am. Fasc. 

 J. no. 212. 1896. De Toni. Syll. Algar. 5: 570. 1907. 



Wolle. Fresh Water Algae. V. Bull. Torr. Bot. Club. 8: 39. 1881. (H. 

 tenuissimus Grun.); Fresh-Water Algae U. S. 277. pi. 196. f. 20, 21. 

 1887. Bennett. 1. c. 114. Wolle and Martindale. 1. c. 606. 



Plant mass floccose; filaments irregularly branched in a squarrose man- 

 ner; branches spreading; sheaths very close, colorless, transparent; trich- 

 omes 3-4.2 mic. in diameter, often interrupted, variously curved, with in- 

 distinct, transverse walls; nearly equal in length to the diameter. 



Massachusetts. Spot Pond, Medford. September 1890. (Collins). 

 Rhode Island. Blackamore Pond. (Bennett). Connecticut. Attached to 

 under side of N u p h a r leaves. Mill Pond, Lantern Hill, Ledyard. Septem- 

 ber 1892. (Setchell). New Jersey. (Wolle). Pennsylvania. (Wolle). 

 Florida. (Wolle). Minnesota. (Wolle). 



442. Hapalosiphon laminosus (Kuetzing) Hansgirg. Ueber den Polymor- 



phismus der Algen. Bot. Centralblatt. 22: 48. 1885. Bornet and Fla- 

 ^ hault. Revis. des Nostoc. Ann. Sci. Nat. Bot. VII. 5: 55. 1887. De 



i Toni. Syll. Algar. 5: 565. 1907. 



Setchell. Notes on Cyanophyceae. — III. Erythea. 7: 47. 1899. Collins. 

 Holden and Setchell. Phyc. Bor.-Am. Fasc. 18. no. 858. 1901. Setchell. 

 The Upper Temperature Limits of Life. Science. 17: 395. 1903. 



Plate XIV. fig. 14, IS- 



Plant mass irregular or expanded, carneous-spongiose or compact, part- 

 ly hardened with calcium carbonate, blue-green; filaments interwoven, 

 showing great variety of form; mature filaments 6 mic. in diameter, with 

 distinct sheath, often constricted at joints, containing a single row of cells, 

 rarely two rows, the cells being spherical depressed, barrel-shaped or cylin- 

 drical, branched; branches unilateral, erect, more slender than the primary 

 filament, composed of long, cylindrical cells; young filaments similar to 

 those of Anabaena, either with or without sheaths, crowded, with a 

 somewhat parallel arrangement, torulose in middle portion, tapering at the 

 ends, sometimes simple, sometimes branched; branches single or in pairs, 

 abruptly bent, with long, narrow cells; heterocysts intercalary, often wider 

 than the vegetative cells, spherical or oblong. 



California. In long, dark, emerald green, penicillate tufts, waving in 

 a stream of hot water (temperature 49-50° C). Arrowhead Hot Springs, 

 near San Bernadino. April 1898. (Setchell). 



"Within the strictly thermal limits (waters over 43°-4S° C), only one 

 member of the higher and heterocysted Cyanophyceae has been noted, 

 viz., Hapalosiphon laminosu s." — Setchell. 



Note. — H. major grows luxuriantly in water of a temperature of 54° 

 C, and even higher. 



443. Hapalosiphon major Tilden. American Algae. Century II. no. 167. 



