EXPLANATION OF PLATES. 



PLATE I. 

 J. H. Blake and W. G. Farlow. 



Fig. 1. Glococapsa crepidinum, Tliuret. 600 diam. 



2. Isactis plana, Tkuret. GOO diam. 



3. Sphcerozyga Carmichaelii, Harv. : a, heterocyst ; b, b, spores. GOO diam. 



4. Lyngbya majuscula, Harv. 400 diam. 



5. Oseillaria subuliformis, Harv. 500 diam. 



6. Calothrix confervicola, Ag. : a, a, liormogonia ; b, b, heterocysts; c, cell of host- 



plant. 400 diam. 



PLATE II. 

 J. H. Blake and TV. G. Farlow. 



Fig. 1. Hormactis Qitoyi, (Ag.) Bornet: a, a, heterocysts. 600 diam. 



2. Bivularia atra, Roth : a, a, heterocysts ; the cross-lines represent the gelatinous 



matrix. 500 diam. 



3. Microcoleus clithonoplastes, Thuret: a, free trichomata projecting beyond the 



ruptured sheath. 500 diam. 



4. Spirulina tenuissima, Kiitz. 900 diam. 



PLATE III. 



J. H. Blake and TV. G. Farlow. 



Fig. 1. Viva Lactuca, (L.) Le Jolis: a, microzoospores which have escaped from mar- 

 ginal cells; b, cells in which zoospores are forming ; c, cells from which zoo- 

 spores have escaped. 500 diam. 



2. Bhizocloni urn, ripar'mm, Kiitz. 20 diam. 



3. Cladopliora lodlevirens, (Dillw.) Harv. 20 diam. 



PLATE IV. 



J. R. Blake and W. G. Farlow. 



Fig. 1. Bryopsis plumosa, (Huds.) Ag. ; portion of upper division of the unicellular 

 frond. 10 diam. 



2. Yaucheria Thuretii, Woronin : a, a, young antheridia ; a', antheridium which 



has discharged its antherozoids ; c, c, oogonia with oospores. 100 diam. 



3. Phyllitis fascia, Kiitz; section of frond with plurilocular sporangia, a, cover- 



ing the surface. 500 diam. 



4. Derbesia tenuissima, (Do Not.) Crouan : a, spores (zoosporangia ?) nearly mature ; 



b, b', cross-partitions forming cell at base of sporangium. 100 diam. 



5. Punctaria plantaginea, (Roth) Grev. ; transverse section of frond : a, plurilocular 



sporangia with zoospores; a', the same when old, after the zoospores have 

 been discharged and the internal cell-walls obliterated. 



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