114 Rhodora [JUNE 
CYANOPHYCEAE. 
* Aphanothece saxicola, Naegeli. Common. 
* Aphanothece microscopica, Naegeli. Common. 
Oscillatoria limosa, Agardh. Scarce. 
Oscillatoria formosa, Bory. Scarce. 
*Nostoc sphaericum, Vaucher. Common. 
* Anabaena catenula, Bornet & Flahault. Fairly common. 
Scytonema crispum, Bornet. Abundant, floating in great masses. 
'The unbranched form only occurred. 
* Tolypothrix tenuis, Kuetzing. Common and intermingled with 
the preceding. 
*Calothrix stagnalis, Gomont. Common on Scytonema crispum. 
Young trichomes blue-green, older trichomes from pale blue to lilac 
in color. Three or four gonidia often present on one filament. 
Sheaths variable, usually thin but sometimes 3 microns thick. 
*Rivularia pisum. Agardh. Common. 
*Rivularia natans, Welwitsch. Common. Forming spherical 
colonies from 4 to 3 mm. in diameter attached to water-plants. 
HETEROKONTAE. 
Ophiocytium cochleare, A. Braun. 
Ophiocytium parvulum, A. Braun. 
CHLOROPHYCEAE. 
*Zygnema pectinatum, Agardh. Common and just beginning to 
conjugate. 
*Spirogyra crassa, Kuetzing. Scarce at border of pond. 
* Mougeotia sphaerocarpa, Wolle. Common. 
Chlamydomonas communis, Snow. Common. 
Gonium pectorale, Muller. Rare. 
Pandorina morum, Bory. Common. 
Characium naegelii, A. Braun. 
Rhaphidium falcatum aciculare, Hansgirg. 
Nephrocytium agardhianum, Naegeli. 
*Tetraedron minimum, Hansgirg. 
