152 Kansas Academy of Science. 



2. Trichomes, 4-7 mic. in diam.; apex of trichome obtuse, 

 straight, rarely curved O. cruenta. 



3. Trichomes, 5.5-8 rnic. in diam.; slightly constricted at 

 joints; apex of trichomes very gradually tapering, hooked 

 or undulating; cells very long near the apex. . . .0. cortiana. 



IV. Apex of trichome tapering, not capitate, trichome regularly terebri- 

 form, forming a spiral throughout the entire length. 



A. Trichomes, 6-8 mic. in diam O. hoi-yana. 



B. Trichomes, 4-6.5 mic. in diam O. terebriformis. 



5. O agardhii Gomont. 



Kansas: Masses at Augusta, August, 1915; Fredonia, 

 August, 1915; Winfield, August, 1915; Cherryvale, 

 November, 1915; Masses at Council Grove, April, 

 1916. 



Missouri (11). 



6. O. anguina Bory. 



Kansas: Marysville, October, 1916, mixed with O. 

 splendida in mats. 



7. O tenuis Agardh. Plate II, fig. 3. 



Kansas: Burlingame, August, 1915; Ottawa, Aj)ril, 

 1916; Pleasanton, August, 1915; Yates Center, 

 August, 1915; Horton, June, 1916. 



Nebraska (24); Colorado (15); Missouri (11). 



8. O. amphibia Agardh. 



^ Kansas: Most common species found. Identified over 



forty times. 

 Iowa (4); Nebraska (3); Missouri (11). 



9. O. snbtilissima. Kuetzing. 



Kansas: lola, August, 1915; Parsons, August, 1915, 

 March, 1916; Yates Center, August, 1915. 



10. O. chlorina Kuetzing. 



Kansas: Lyndon, August, 1915, March, 1916. 

 Nebraska (3). 



11. O. angustissima W. & G. S. West. 

 Kansas: Paola, August, 1915. 

 Iowa (4). . 



12. O. splendida Greville. Plate II, fig. 4. 



Kansas: Chanute, August, 1.916; Cotfeyville, August, 

 1915, March, October, 1916; Cherryvale, November, 

 1915, October, 1916, along with O. terehnforrruis 

 forming a mat of deep blue-green on edge of reser- 

 voir. Horton, June, October, 1916; Marysville, 

 October, 1916; Osawatomie, October, 1916; Pleasan- 

 ton, August, 1915; Winfield, August, 1916. 



Missouri (11). 



13. O. amoena Kuetzing. 



Kansas: Mound City, March, 1916; Leavenworth, 

 August, 1916; lining reservoir with deep blue-green 

 carpet. 

 IJt. O brevis Kuetzing. Plate II, fig. 5. 



Kansas: Burlingame, March, August and November, 

 1915; April, 1916; Coffeyville, July, 1916; Fort 

 Scott, April, 1916; Horton, June, 1916; Indepen- 

 dence, August, 1915; March, 1916. 

 15. O. cruenta Grunow. 



Kansas: Masses, Leavenworth, August, 1915, Novem- 

 ber, 1915, August, 1916. 



I 



