Evolution of Plants 



305 



sets forth the distribution of the genera and species of the 

 different famihes that now hve in fresh and salt water re- 

 spectively. 



Distributional Table for Algae-Fungi 



Group 



Group 



Fresh- 

 water 



Marine 



eg 



fcH 



05 

 O 



a, 



!/2 



S=i 



O 



en 



C/2 



C\ anophycese. . . . 

 Desmidiacese . . . . 

 Zygnemaceae . . . . 

 Mesocarpacese . . . 



Volvocacese 



Tetrasporaceae... . 

 Pleurococcacefe. . 

 Protococcaceae. . . . 

 Hydrodictyacese . 



T'lvaceae 



t lothricacese 



Chaetophoraceae. 



Mycoidaceae 



Oedo-Coleoch'ae. . 

 Cladophoraceae . . 

 Vaucheriaceae. . . . 



Characeae 



Caulerp-Bryop'ae. 



73 



31 



4 



2 



20 



11 



33 



13 



4 



5 



5 



17 

 5 

 3 

 6 

 2 

 6 



548 



1029 



108 



32 



27 



28 



110 



48 



36 



29 



29 



86 



10 



184 



108 



26 



34 



8 



2 

 1 

 1 

 3 



6 



2 

 6 

 1 



105 



20 



Valoniaceae 



Diatomaceae penn. . . 

 Diatomaceae 



centricae 



Gymnodiniaceae 



2 Prorocentraceae 



3 Peridiniaceae 



3 Phaeophyceae 



Litho'ae-Pleuro'ae . 

 Phaeophyceae 



marinae 



8 Bangiaceae 



1 Lemaneaceae 



I He] minthocladiaceae . 



69;Rhodophyceae 



Bacteriaceae 



Fungi 



49 

 4 



193 



Total. 



12 55 

 44 1287 



59 

 5 

 3 



21 



145 

 1 



7 



291 



4 



10 



1046 



35 



10 



105 



759 

 33 



18 



1975 



50 



200 



658 6018 



The above reveals some suggestive peculiarities. If, ex- 

 cepting the Cyanophycese, account be taken of the next sixteen 

 groups along with the group of the Pennatce, or simpler diatoms, 

 which together represent the lowest and most primitive algae, 

 206 genera and 3168 species are fresh- water, while 71 genera 

 and 1430 species are marine. So, if account be taken of those 

 which show simplest individual structure, simplest cell struc- 

 ture, simplest modes of reproduction, and widest geographical 

 distribution, the fresh- water species and genera greatly pre- 

 dominate. But when the highest and almost assuredly the 

 four most recent divisions of the "Centric" diatoms, the brown 

 and the red algae, as well as the highest green alga^ are com- 

 pared, it is found that there are 24 genera and 258 species in 

 fresh water, and 505 genera with 4233 species that are marine. 



