NO. 5 COLONIAL FORMATIGX OF GREEN ALGAE MEIER 7 



GROWTH AND GENERAL DEVELOPMENT 



In the majority of the varieties studied, the growth and develop- 

 ment of the colony attained its maximum at the end of 30 days, and 

 with the exception of the algae listed below, the colonies showed no 

 increase in size after the first month. These exceptions are Chlorella 

 vulgaris in 5, i, 2, 7, 8 and 9; Palmcllococcus variegatus in 5, 2, 3, 7, 

 8, and 9 ; Chlorella vulgaris var. in all nine treatments ; Chlorococcum 

 viscosum in all nine treatments ; Scenedesmus quadricauda in 7, 8, 

 9 ; Oocystis tiaegelii in 4 and 6 ; Hcterococcus viridis in 2 and 5 ; 

 Scenedesmus chlorelloides var. in 2. 



In general, the colonies made the same amount of growth and were 

 approximately the same size in all nine treatments. There were strik- 

 ing exceptions, however, in the following cases as indicated in the 

 table and plates 2 and 3. Palmellococcus variegatus in 2 and 5; 

 Scenedesmus chlorelloides var. in 2 ; Chlainydoruonas intermedia in 4; 

 Hetcrococcus viridis in 5 and 2 ; Cystococcus cohaerens var. in 2 and 3 ; 

 Chlorococcum viscosuui in i, 2, 3. and 9; Chlorella vulgaris var. in 



2, 4, 5, and 6; and Chlorella vidgaris in i and 5. 



Those cultures that showed remarkably poor growth were Chloro- 

 coccum viscosum in 6; and Chlorella vidgaris in 4. 6, and 3. 



There were striking morphological dififerences in some colonies of 

 the same alga subjected to different conditions. The disks of Chlorella 

 vulgaris in i, 5, 8 were firm and sectored ; in 3, 4, 9 they had a moist 

 appearance ; and in 2, 6, 7 they appeared to be very dry. Coccomyxa 

 viridis had very firm colonies in i, 5, 8 and in 2, 6, 7, but those in 



3, 4, 9 were very fiuid. Cystococcus irregularis in i, 3, 2 and 6 were 

 characteristically wrinkled, while those in 7, 8 and 9 were smooth 

 little peaks. For Scenedesmus quadricauda in i, 4, 6 all the three 

 colonies were run together in brilliant liquid masses, in 2 and 7 the 

 colonies were finely nerved ; while in 8 and 9 they were mottled and 

 distinct. Chlorococcum viscosum in 2, 6 and 7 had dull disks while 

 the other six treatments caused glistening and brilliant colonies. The 

 colonies of Stichococcus hacillaris were firm, and rough with tiny 

 excrescences, shining brightly with the exception of those in 3, 4, 9 and 

 2 which were dull. The cultures of Oocystis naegelii were smooth, 

 brilliant, and fluid with the exception of 6 and 7, which were wrinkled, 

 dry, and dull, and 2, which had smooth, dry, and dull colonies. The 

 colonies of Chlaniydomonas intermedia were brilliant in three treat- 

 ments but in 2, 6, 7 were dull, while 3, 4, 9 caused a curdled ap- 

 pearance. Hetcrococcus viridis had dry, dull disks in i, 8. 2, 6, and 7 

 but brilliant, moist ones in 5, 3, 4, and 9. Chlorella viscosa in 2, 6, 7 



