3(> 



MISSOURI BOTANICAL GARDEN. 



Oscillatoria tenuis Ag. Crescent pool, forming a dark 



stratum on the floor of the pond, 



associated 



dO 



Mar., Apr. Abundant. 



Oscillatoria chalybea Mertens. Arboretum 



mo 



», 



/ 



Bory. 



stream. As- 

 May. Common. 

 Arboretum pond. Nelum- 



bium pool. Apr., May. Rare. 



Oscillatoria limosa Ag. Lagoon. Crescent pool. Arbore- 

 tum stream. Earth. This species occurs in greater abund- 

 ance and in more habitats than any of the others. At the 



f the Arboret 



quantity. In the 



f 



stream very little is 



present. The upper half of the stream flows rapidly over 

 rocks, while the lower half, into which sewage enters, flows 

 sluggishly. Here in the sluggish part of the stream 0. limosa 

 covers the floor in a thick stratum, which now and then 

 breaks up into tufts and floats away or is forcibly all carried 

 away by freshets, after which, in a short time, the floor of 

 the stream is recovered. Sept. to May. 



Oscillatoria splendlda Greville. Crescent pool, 

 with 0. limosa and 0. tenuis. Common. 



Oscillatoria limnetica Lemm. Arboretum stream. Rare. 



Lyngbya Digueti Gomont. Attached to Stigeoclonium 



Associated 



Rare. 



Waterfall and to Vaucheria in Arboretu 



Lyngbya Lagerheimii (Mob.) Gomont.* 



Phormidium uncinatum 



Lagoon. 



stratum. 



Gomont.* 



Gomont. On rocks West 



c 



Very abundant, forming a thick dark green 

 Sept. to Dec, Apr., through May. 



West Lagoon, associated with Os- 



major 



cillatoria limosa. Sept. to Dec. Common 



NOSTOCACEAE. 



Anabaena circinalis (Kiitz.) Raben. Quiet water. La- 



goon. 



Rare. Oct. 



Anabaena Flos-aquae (Lyngb.) Breb. Nelumbium pool. 

 Abundant in Lagoon. (See Clatlirocystls.) Sept. to Oct. 



