244 FLORA OF MOUNT DESERT. 



BULBOCOLEON, Prings. 



B. piliferum, Prings. 



In fronds of Castagnea virescens from tide pools, Seal Har- 

 bor (Collins). 



ULOTHRIX, Kuetz. 



U. flacca (Dillw.), Thuret. 



On piles of wharves and on rocks. Seal Harbor; Southwest 

 Harbor (Collins). 



U. isogona (Sm.), Thuret. 



On stones near Life Saving Station, Little Cranberry Isle 

 (Collins). 



* U. zonata, Kuetz. 



In fresh water (Holden). 



CONFERVA, Link. 



* C. affinis, Kuetz. 



In fresh water (Holden). 



ULVACE.E. 



TETRANEMA, Aresch. 



Frond consisting at first of a single series of cells, subse- 

 quently of two (or four?) series arranged symmetrically. 



T. percursum (Ag.), Aresch. 



Forming light green or yellowish masses in warm upper 

 pools, usually mixed with various species of Enteromorpha, 

 Cladophora, etc. The frond consists at first of a single con- 

 ferva-like filament, which soon divides into two series of cells, 

 set side by side, the cells, usually a little longer than broad, 

 being set symmetrically, the cross walls exactly opposite. The 

 filaments are unbranched, usually .01 to .016 mm. diam. In 

 upper tide pools. Near Seal Harbor (Collins). 



