Semi-Centennial Volume. 153 



16. O cortiana Meneghini. 



Kansas: Chanute, August and November, 1915, 

 April, 1916. 



17. O. boinjana Bory. 



Kansas: Much, Emporia, November, 1915. 



18. O. terebriformis Agardh. 



Kansas: Kansas City, August, 1915; Cherryvale, Oc- 

 tober, 1916; Paola, August and November, 1915; 

 Washington, August, 1915. 



2. Spii'idina. 



Key tn Sjii'cies. 



I. Trichomes. 1.2-1.7 mic. in diam., forming a loose irregular spiral. 



S. major. 

 11. Trichomes, 2 mic. in diam., flat, forming continuous band (untwisted, 



forming a complete ring) with one to four turns S. duplex. 



Uh S. major Kuetzing. Plate II, fig. 6. 



Kansas: Atchison, August and November, 1915; 

 Douglass, August, 1915; Coffeyville, October, 1916; 

 Osawatomie, July, 1916, velvety, dark blue-green 

 masses, slimy, mixed with O. amphibia, October, 

 1916; Winfield, August, 1915. 

 Iowa (4) ; Nebraska (3) ; Colorado (15) ; Missouri 

 (11). 



20. S. duplex WoUe. 



Kansas: Coffeyville, October, 1916. 



3. PJionnidium. 



Ken '" f^peciex. 



I. Apex of trichome straight, not capitate, trichomes 3-5 mic. in diam., 

 not constricted at joints, cells 2-4 mic. in length; transverse walls 



conspicuous P. papyraceum. 



II. Apex of trichome straight, briefly tapering, capitate trichomes 5.5- 

 11 mic. in diam., not constricted at joints, cells 2-4 mic. in length. 



P. subfuscum. 



21. P. papyraceum Agardh. 

 Kansas: Horton, June, 1916. 



22. P. subfuscum Kuetzing, 

 Kansas: lola, December, 1915. 



4. Lyngbya. 



Key to Species. 



I. Trichomes not more than 2 mic. in diam.; sheaths thin, colorless, 

 filaments straight or curved. 



A. Filaments 1.9 mic. in diam.; cells 1-1.5 mic. long, contents pale 

 steel color L. nana. 



B. Filaments 1.5-1.8 mic. in diam.. cells up to 3.6 mic. long, contents 

 pale blue-green L. subtilis. 



II. Trichomes 2-6 mic. in diam.; sheaths usually thin, and colorless, but 

 sometimes thick and yellowish. 



A. Sheaths often becoming thick and lamellose; trichomes 2.5-6 

 mic. in length ; filaments coiled L. lutea 



B. Sheaths thin and colorless; plant mass light green; trichomes 

 2-3 mic. in diam., not constricted at joints; cells 1-3.7 mic. in 

 length L. digueti. 



C. Sheaths colorless and firm; plant mass dull blue-green; trichomes 

 4-6 mic. in diam., not constricted at joints; cells 2.3-3 mic. in 

 length Li. serugineo-CR'ridea 



