

ALGAL FLORA OF THE MISSOURI BOTANICAL GARDEN. 47 



perpendicularly from a shelf above. You 



March. Zoospores were pro- 



The 



duced abundantly in the fall. 



Microthamnion Kutzingianum Nag. Crescent 

 Stigeoclonium glomeratum. Rare. April. 



Palmodictyon viride Kiitz. Fountain pond a 

 mentous algae and partially decaying aquatic pi; 

 cells of the thalli here were 6.4-9.6^ in diam., rarely 12.8/*. 

 Rare. Oct., Nov., May, June. 



Pleurococcus vulgaris Menegh., not Nag. On the saturated 

 surface of rocks over which water seeps. Waterfall stream. 

 Common. Sept., June. 



■ 



SlPHONOCLADIALES. 



CLADOPHORACEAE. 



Cladophora canalicularis (Roth) Kiitz. Attached to 

 rocks in the bed of the rapidly running Arboretum stream. 

 This Cladophora covered the rocks with a thick coat of cool 

 green color during the fall, first observed in Oct., which be- 

 came grayish, yellowish and dingy during the winter, when 

 it became covered with a thick coat of diatoms. The diatoms 

 began to diminish in number near the first of April, leaving 

 the Cladophora looking ragged, limp and unhealthy. Some 

 fresh new branches were then sent out from the old weather- 

 beaten thalli, and young plants also began to grow. Some of 

 the cells were filled with dense protoplasm resembling the 

 prolific cells of Pithophora. 



Pithophora Mooreana Collins MS. 2 



This Pithophora was first observed in the garden by Dr. 

 Moore in Nelumbium pool. The description by Mr. Collins 

 is not yet published. The plants were growing in Sept. and 

 Oct. in the small Nelumbium pools. In Oct. spores were 

 very rarely seen. After the first frost spores were formed 



2 Closely related to P. Summatrana but differing in dimensions and 

 in the grouping of spores, which are borne in groups of one, two or 

 three in P. Mooreana, the spores of P. Summatrana being borne 



singly. 



