352 PHARMACEUTICAL BOTANY 
weeds belonging to this class have long been sources of iodine, 
potash and sodium. 
There are four orders of brown algae, viz., the Pheosporales, 
Laminariales, Dictyotales and the Fucales. Types of three of these 
will be considered. : 
A FrtaMentous Brown ALGA, Ecrocarpus SILICULOSUS.— 
Ectocarpus, a representative of the Order Phaosporales, occurs as 
Fic. 256.—Fossil diatoms: a, a, a, Gaillonella procera and G. granulata; 6, 6, 
Surirella plicata; c, Surirella craticula; d, d, d, Gaillonella (Melosira) biseriata (side view); 
e, Gomphonema gracile: f, Cocconema fusidium; g, Tabellaria vulgaris; h, Pinnularia dacty- 
lus; i, Pinnularia nobilis; k, Surirella caledonica; 1, Synedra ulna. (After Carpenter.) 
tufts of branching filaments, each of whichis many celled. ‘These 
tufts are found on eelgrass or other algz as well as attached to 
pilings of wharves in salt water. It is a striking illustration of the 
simplest form of brown algae and serves to show the beginning of 
a more complex form of reproduction than that observed in the 
forms studied up to this time. On examination of a filament we 
find it to consist of many cells joined end to end. A single cell 
has a cell wall of cellulose. Just within the cell wall there is a 
layer of protoplasm. Going toward the center we find an irreg- 
ular chromatophore containing a brown pigment called phyico- 
phein. From certain cells of the filament spherical to elliptical 
