46 Minnesota Algae 



Plate II. fig. 41. 



Colonies spherical, hard, solitary or in clusters, blue-green becoming 

 dark-colored; tegument confluent, colorless; cells 1.2-2.3 mic. in diameter, 

 3 mic. in length, spherical or oblong, somewhat seriate, crowded at the 

 periphery, few in the interior; cell contents homogeneous, light blue-green. 



Alaska. Plentiful on water-moss in running fresh water. Near Iliuliuk, 

 Unalaska. (Setchell and Lawson). 



Genus CHLOROGLOEA Wille. Algol. Notizen. I-VI. S- pl. i- 1900. 



Colonies irregularly lobed; tegument thin, not lamellose; cells spherical 

 or oval, arranged in radiating series; reproduction by cell division in one 

 direction. 



106. Chlorogloea tuberculosa (Hansgirg) Wille. Algol. Notizen. I-VI. 5. 

 pl. I. 1900. De Toni. Syll. Algar. 5: 118. 1907. 



Tilden. American Algae. Cent. IV. no. 382. 1900. (Pringsheimia 

 scutata cladophorae Tilden). 



Plate 11. fig. 42. 



Colonies disc-shaped, epiphytic, greenish; cells i-l.S mic. in diameter, 

 2 mic. in length; ellipsoid, after division somewhat spherical. 



Canada. On Cladophora in tide pool. Minnesota Seaside Station. 

 Vancouver Island, British Columbia. August 1898. (Tilden). 



Family II. CHAMAESIPHONACEAE 



Plants often showing a difference between basal and apical regions, 

 solitary or associated in families or colonies, usually epiphytic or attached 

 to shells; reproduction by cell division, by division of filaments into frag- 

 ments, or by means of non-motile gonidia formed by the division of the 

 contents of a mother cell or gonidangium. 



I Reproduction by cell division and by gonidia; cells usually united in 

 colonies 



1 Colonies somewhat spherical or hemispherical, usually consisting of 



several layers of cells Pleurocapsa 



2 Colonies disc-shaped, usually consisting of a single layer of cells 



Xenococcus 



3 Colonies forming branched filaments Hyella 



I] Reproduction by gonidia only 



1 Gonidia formed by simultaneous division of the entire contents of 



gonidangium Dermocarpa 



2 Plants not usually united in colonies; gonidia formed by successive 



constrictions of apical portion of contents of gonidangium 



Chamaesiphon 



