48 



MISSOURI BOTANICAL GARDEN. 



sparingly. Some Pithophora kept in a glass jar in water 

 from the pool was observed in Jan. to have abundant spores. 

 The plants at this time broke up easily. The akinetes were 



in a group. Spores 



uncomm 



f 



intercalary. In a few instances swellings globular in form 

 just below the akinete at the top of the cell, were noted. This 

 swelling was preliminary usually to the formation of a 

 spore, but in some cases there appeared to be not enough 

 of protoplasm to form a second spore in the cell, while in 

 other cases twin spores were developed in a cell. Twin spores 



were usually observed 



the branches, not in the main 



stem. Akinetes of the main stem are cylindrical (square 

 to rectangular in outline) little, if any, swelled. Akinetes 

 of the branches were cask shaped. In twin groups the cells 

 were either similar in shape or one cylindrical and one cask 

 shaped. The branching is one ranked. In only two cases 

 were rhizoid-like structures observed. 



The measurements 



are: 



Akinetes. 



L. 

 W 



Side Branches 

 Main Stem 



Max. 



380/x 

 114 



665— 

 114 



Av. 



114/i 

 95 



114/x 

 142.5/* 



Min. 



95/z. 

 57 



Pithophora Oedogonia (Mont,)' Wittr. t Fountain pond. 

 Oct., June. Akinetes produced in June. Rather rare. 



Rhizoclonium 



(Ag.) Kiitz.* 



SlPHONALES. 



VAUCHERIACEAE. 



^aucheria sp. Mar 



Submerged or terrestrial 

 of Arboretum stream. 







