Myxophyceae 33 



Almanac and Annual for 1902. 113. 1901; American Algae, Cent. V. no. 498. 

 1901; Algae Collecting in the Hawaiian Islands. Postelsia: The Year Bopk 

 of the Minnesota Seaside Station. 1:146. 1902. ^ 



Plate II. fig. 16. 



Plant mass gelatinous, more or less globose, tuberculose or angular, 

 bright emerald green, sometimes confluent and then lobed; sheaths difflu- 

 ent; cells s-6.5 mic. in diameter, 7.7-1 1 mic. long, oblong or ovoid, often 

 spherical after division; cell contents blue-green. 



Massachusetts. Cambridge. (Farlow). Connecticut. In free swim- 

 ming gelatinous masses of a yellowish or bluish green color, globular when 

 young, later becoming irregular in shape. Norwich. September 1892. 

 (Setchell). New Jersey. Floating on ponds. (Wolle). Hawaii. Form- 

 ing free-swimming, blue-green tuberculose, globose or flattened soft masses, 

 floating in ditch in rice field near beach. Aiea, Oahu. June 1900; in brack- 

 ish, stagnant water. Meheiwi, Makao, Koolauloa, Oahu. June 1900. (Tilden). 



Genus ]\IICROCYSTIS Kuetz. Linnaea 8:372. 1833. 



Colonies spherical or somewhat spherical, solid, finally becoming hol- 

 low and lobed, single or associated in clusters, containing large numbers of 

 cells, surrounded by a colorless, gelatinous tegument; cells spherical, oval 

 or elliptical; cell contents green or blue-green, often showing vacuoles; 

 reproduction by cell division in three directions. 



I Cells spherical. 



1 Colonies more or less spherical, usually containing several daughter 



colonies each surrounded by its own tegument; cells 2-4 mic. in 

 diameter M. ichthyoblabe 



2 Plant mass dull yellowish becoming olive; colonies 30-70 mic. in diam- 



eter; cells 2.2-4 mic. in diameter M. donnellii 



3 Colonies spherical, flattened, orbicular, lens-shaped, sometimes con- 



fluent, surrounded by a thick, lamellose common tegument; cells 

 3-4 mic. in diameter M. marginata 



4 Colonies more or less spherical or oblong, with an indistinctly 



limited tegument, pale or yellowish-green; cells 4-6.5 mic. in diam- 

 eter. M. flos-aquae 



II Cells oval or oblong, sometimes almost spherical. 



1 Colonies spherical, oblong or flattened, sometimes containing several 



daughter colonies each surrounded by its own tegument; cells 1-1.5 

 mic. in diameter, 3-5 mic. in length, -oblong M. elabens 



2 Plant mass pulverulent, bright glaucous or whitish blue-green; col- 



onies spherical or oblong; cells 2-3 mic. in diameter, somewhat 

 spherical or oval M. pulverea 



3 Plant mass irregular, firm, gelatinous, pink, brown or green, growing 



in very salt water; cells 2.5-4 mic. in diameter, 6-7 mic. in length, 

 oblong or elliptical M. packardii 



4 Plant mass mucous, floccose, amorphous, sky-blue; colonies somewhat 



