Hormidium Klehsii G. M. Smith 1933, p. 385 

 PL 6, Fig. 4 

 Long unbranched filaments in which there is no basal-distal dif- 

 ferentiation. Cells cylindrical, not constricted at the cross walls. 

 Chloroplast a parietal plate covering only a small portion of the cell 

 wall. Cells 5.8-6/A in diameter, 15.6-25/i. long. 

 In Sphagnum bogs and roadside ditches. Wis. 



URONEMA Lagerheim 1887, p. 517 



Simple, unbranched filaments which are always attached. Cells 

 cylindrical, the basal cell forming an organ of attachment, the ter- 

 minal cell tapering unsymmetrically to a blunt boint. Chloroplast a 

 parietal plate, Vo to % the length of the cell; with 1 or 2 pyrenoids. 



Uronema elongatum Hodgetts 1918, p. 160 

 PL 5, Fig. 5 



Cells cylindrical, as much as 13 times their diameter in length, 

 and 5-10/x, wide. Chloroplast a parietal folded plate extending for 

 % of the circumference and V2 to % tlie length of the cell; with 2 

 pyrenoids. Terminal cell unsymmetrically tapering to a blunt point 

 and often slightly curved. 



This plant should be compared with germhngs and young stages 

 in the development of Ulothrix and such members of- the Chaeto- 

 phoraceae as Stigeocloniimi and Chaetophora. The separation of 

 Uronema from Ulothrix has been questioned; but the tapering apical 

 cell persisting through maturity, the permanent attachment of the 

 plants, and the type of basal holdfast of Uronema seem to be suffi- 

 cient justification for the retention of the two names. 



Attached to filamentous alo;ae and other submerged aquatics in 

 shallow backwaters. Mich., Wis. 



STICHOCOCCUS NaegeU 1849, p. 77 



Simple unbranched filaments of short, cylindrical, undifferentiated 

 cells, which are often loosely connected, so that interrupted series 

 are formed. Chloroplast a parietal folded plate, covering V^ or less 

 of the cell wall, with 1 pyrenoid. Filament fragmenting easily to 

 form short sections or solitary cells, which by vegetative division 

 rebuild longer, curved (sometimes coiled) or straight filaments. Fre- 

 quenting moist substrates in association with Protococcus [Pleuro- 

 coccus]; also in algal mixtures encrusting submerged wood, or on 

 aquatic plants. 



[98] 



