LICHEN ALGAE 



57 



Coccomyxa subellipsoidea is given' as the gonidium of the primitive 

 lichen Botrydina vulgaris {¥[g. 25). The cells are surrounded by a common 

 gelatinous sheath. 



Fig. 34. Coccobotrys Verritcariae Chod. 

 from culture x 800 (after Chodat). 



Fig. 25. Coccomyxa subellipsoidea Acton. 

 Actively dividing cells, the dark portions 

 indicating the chloroplasts x tooo (after 

 Acton). 



5. DiPLOSPHAERA Bial.' D. Chodati was taken from the thallus of 

 Lecanora tartarea and successfully cultivated. It resembles Protococcus, but 

 has smaller cells and grows more rapidly ; it is evidently closely allied to 

 that genus, if not merely a form of it. 



6. Urococcus Kiitz. Cells more or less globose, rather large, and 

 coloured with a red-brown pigment, with the cell-wall thick and lamellate, 

 forming elongate strands of cells (Fig. 26). Recorded by Hue' in the 

 cephalodium of Lepolichen coccophora, a Chilian lichen. 



Fam. Tetrasporaceae. Cells in groups of 2 or 4 surrounded by a 

 gelatinous sheath. 



I. Palmella Lyngb. Cells globose, oblong or ellipsoid, grouped without 

 order in a formless mucilage (Fig. 27). Among lichens associated with 

 Palmella are the Epigloeaceae and Chrysothricaceae. 



Fig. 26. Urococcus sp. Group of cells 

 much magnified (after Hassall). 



Fig. 27. Palmella sp. x 400 (after Comere). 



2. Gloeocystis Naeg. Cells oblong or globose with a lamellate 

 sheath forming small colonies ; colour, red-brown 

 (Fig. 28). This alga along with Urococcus was 

 found by Hue in the cephalodia of Lepolichen 

 coccophora, but whereas Gloeocystis frequently occu- 

 pies the cephalodium alone, Urococcus is always 

 accompanied by Scytonema, the normal gonidium 

 of the cephalodium. 



Fig. 28. Gloeocystis sp. x 400 

 (after Comere). 



' Acton 1909. 



^ Bialosuknia 1909. 



' Hue 1905. 



