334 PHARMACEUTICAL BOTANY 
plants, are merely sheets or cylinders of many celled filaments, 
closely arranged and connected by protoplasmic connections. 
They contain chlorophyH, and so can use the CO; and H.O in 
the same manner as higher plants, ¢.g., in building up food and 
providing for their own nutrition. In addition to chlorophyll, 
some contain one or more additional pigments. Asexual repro- 
Fic. 243.—Blue-Green Algae. A-C. Gloeocapsa polydermatica. A, single cell in 
which division has begun; B, two daughter cells resulting from fission; the cell on 
the left is dividing; C, colony of four granddaughter cells; D, fixed and stained cell 
of Rivularia pisum. The net-like central body is the nucleus. X 3000. fy Pe, 
Oscillatoria princeps. E, terminal portion of a filament; P, portion of a filament 
showing a dead cell. X 540. G, as maller species of Oscillatoria. H-K, Nostoc. 
H, portion of filament; A, heterocyst; I, portion of a filament with spores (sp); 
J; spore; K, short filament produced by germinating spore. X 650. (A to C, 
after Strasburger; D, after Haupt; H, I, F, K, after Bornet.) 
duction is accomplished by motile or non-motile spores. Sexual 
reproduction occurs in all but the simpler forms. The gametes 
may be motile or non-motile. The female gamete is lodged 
within an od6gonium or carpogonium both of which are unicel- 
lular female sexual organs. Archegonia are absent in this group. 
Crass I.—CyANopuyce#, THE BLUE-GREEN ALG 
Plants which are sometimes termed blue-green alge. They 
contain chlorophyll, a green \ pigment, and phycocyanin, a blue 2 
pigment, a combination giving a blue-green aspect to most of the 
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