PLATE IV 



Fig. I. Mastodia tesselata Hook. f. and Harv. growing on the + vertical 

 north-facing side of a bird-frequented granodiorite rock on Goudier 

 Islet, Port Lockroy. Above are seen stages in the transition into the 

 free-living alga Prasiola crispa, which replaces the Mastodia on the 

 zenith surface of the rock. Also present : Caloplaca elegans Th. Fr. 

 \ nat. size. Phot. I.M.L., 20. xii. 1944. 



Fig. 2. Verrucaria Racovitzae Vain. ; holotype specimen (above). The 

 lower, coarsely rimose thallus is Verrucaria elaeoplaca f. glaucoplaca 

 (Vain.) M. Lamb, x 4. 



Fig. 3. Verrucaria famelica Darbish. ; syntype specimen in herb. Kew. 

 X4. 



Fig. 4. Verrucaria cylindrophora Vain. ; part of the holotype specimen. 

 X4. 



Fig. 5. Microglaena antarctica M. Lamb ; part of the holotype specimen. 



Fig. 6. Verrucaria dispartita Vain. ; part of the holotype specimen, x 4. 

 Fig. 7. Verrucaria psychrophila M. Lamb ; part of the holotype specimen. 



x4- 

 Fig. 8. Verrucaria serpuloides M. Lamb ; part of the holotype specimen. 



X4. 



Fig. 9. Verrucaria tesselatula f. dermoplaca (Nyl.) M. Lamb; part of 

 syntype specimen in herb. Kew. x 4. 



