8 



ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Table 3. -Dominant genera 1 of algae observed in the phytoplankton of the United 



States - Continued 



Genus 



Number of 

 dominances 2 



Percent 



Trachelomonas 



Coelastrum 



Actinastrum 



Pediastrum 



Micractinium 



Cryptomonas 



Oocystis 



Dinobryon 



Sphaerocystis 



Surirella 



Cylindrospermum 



Chroomonas 



Pandorina 



Euglena 



Phormidium 



Eunotia 



Raphidiopsis 



Kirchneriella 



' Comprising 15 percent or more of sample. 



2 Based on 17,959 samples 



3 Not a commonly occurring genus (see tabli 2) 



Table 4.-Taxonomic groupings of commonly occurring and dominant genera of algae of 



the United States 



CHLOROPHYTA (Green algae) 



Actinastrum 



Ankistrodesmus 



Chlamydomonas 



Chodatella 



Coelastrum 



Cosmarium 



Crucigenia 



Dictyosphaeriurn 



Golenkinia 



Kirchneriella 



Micractinium 



Oocystis 



Pandorina 



Pediastrum 



Scenedesmus 



Schroederia 



Selenastrum 



Sphaerocystis 



Tetraedron 



Tetrastrum 



EUGLENOPHYTA (Euglenoids) 



Euglena 



Trachelomonas 



CHRYSOPHYTA (Chrysophytes and diatoms) 



A chnanthes 



Amphora 



Asterionella 



Cocconeis 



Cyclotella 



Cymbella 



Diatoma 



Dinobryon 



Epithemia 



Eunotia 



Fragilaria 



Gomphonema 



Gyrosigma 



Melosira 



Navicula 



Nitzschia 



Pinnularia 



Rhoicosphenia 



Stephanodiscus 



Surirella 



Synedra 



Tabellaria 



PYRROPHYTA (Dinoflagellates) 



Glenodinium 



Peridinium 



CRYPTOPHYTA (Cryptomonads) 



Chroomonas 



Cryptomonas 



CYANOPHYTA (Blue-green algae) 



Agmenellum 



Anabaena 



Anacystis 



A phanizomenon 



Cylindrospermum 



Gomphosphaeria 



Lyngbya 



Oscillatoria 



Phormidium 



Raphidiopsis 



