12 Minnesota Algae 



Plants 3 mic. in diameter, 6 mic. long just before dividing, slightly 

 elongated, single or united by strands of transparent jelly; cell walls very 

 thin, scarcely visible; cell contents pale bluish-green. 



California. Floating in myriads in hot salt water, near Key Route 

 power house. Oakland. September 1905. (Gardner). 



Genus CHROOTHECE Hansgirg. 

 Oesterr. Bot. Zeit. 34: pi. I. 1884. 



Plant mass somewhat gelatinous, dark-yellowish; plants cylindrical or 

 oblong-conical, with rotund ends, single or in pairs; sheaths wide, lamellose, 

 hyaline, increasing greatly in thickness at one pole; cell contents distinctly 

 granular, bright blue-green or orange-yellow; reproduction by division of 

 the cells in one direction only. 



I Plants 18-24 mic. in diameter C. richteriana 



II Plants 1.5 mic. in diameter C. cryptarum 



III Plants 1 1-12.5 mic. in diameter C. monococca 



23. Chroothece richteriana Hansgirg. Bot. Notiser. 128. 1884; Prodromus 



der Algenflora von Bohmen. 2: 134. f. 45. 1892. De Toni. Syll. Algar. 

 5:29. 1907. 

 Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 13. no. 702. 1900. 

 Collins. The Algae of Jamaica. Proc. Am. Acad. Arts Sci. 37:239. 1901. 



Plate I. fig. 12. 



Plant mass somewhat gelatinous, thick, more or less expanded, blue- 

 green or yellowish, becoming darker; plants 18-24 mic. in diameter, once to 

 twice as long as wide, single or in pairs; sheaths up to 6 mic. in diameter, 

 somewhat colorless. 



Bermudas. On rocks. The Flats. Bermuda. January 1900. (Farlow). 

 West Indies. Among other algae, in small quantity. Montego Bay. (Pease 

 and Butler). 



24. Chroothece ? cryptarum Farlow in Collins, Holden and Setchell. Phyc. 



Bor.-Am. Fasc. 16. no. 752. 1900. De Toni. Syll. Algar. 5:30. 1907. 

 Plant mass irregular, gelatinous, widely expanded, of a pale blue-green 

 or dirty yellow color; plants 1.5 mic. in diameter, 3 mic. in length, oblong 

 or rod-shaped; sheaths gelatinous, colorless, becoming lamellate and devel- 

 oping below into densely branching Urococcu s-like stalks, 7-9 mic. in 

 diameter, 25-50 mic. in length; cell contents blue-green, without definitely 

 shaped chromatophore; cell division usually in one, occasionally in two 

 directions. 



Bermudas. On calcareous rocks in caves by the seashore. Bermuda. 

 January 1900. (Farlow). 



25. Chroothece monococca (Kuetzing) Hansgirg. Prodromus der Algen- 



flora von Bohmen. 2: 134. 1892. De Toni. Syll. Algar. 5:30. 1907. 

 Plant mass amorphous, gelatinous, blue-green; families 15-20 mic. in 

 diameter; plants 11-12.5 mic. in diameter, up to twice as long as broad, ellip- 



