SYSTEMATIC ACCOUNT 15 



in a drier position) with fine reticulately anastomosing cracks in the thicker parts of the thallus around 

 the perithecia. Gonidial algae bright green, 6-8 n diam. Excipulum spherical, (100-) 165-195 // diam., 

 with wall 18-21// thick; inner 9// dark brown, the outer part pale brown. Spores 9-i2(-i3)x4-5- 

 6-o{-j) ju. The minute roughening of the thallus is very inconspicuous, not to be compared with the 

 punctate or wrinkled scabrosity of some other marine species {Vernicaria scotina, etc.). 



Geographical Distribution. Previously known only from the type locality (west Graham Land : 

 Cape Anna, on the mainland coast between Cape Charles^ and Cape Renard). 



Verrucaria elaeoplaca Vainio (Fig. 3/; PI. II, fig. 2; PI. Ill, figs, i, 2) 



i903> P- 37. Pl- i. fig- 6. 



Verrucaria glaucoplaca Vainio, 1903, p. 37, pi. i, fig. 5; Hue, 1915, p. 182. 



West Graham Land. Palmer Archipelago : Port Lockroy, Goudier Islet ; near summit of islet, altit. 

 about 7 m. on granodiorite rocks irrigated intermittently by snowmelt water; F.I.D.S., 29. ii.1944 

 (no. 1151 ^r. p.); 26. iii. 1944 (no. 1179); 7. v. 1944 (no. 1234); 26. xi. 1944 (no. 1801); 28. xi. 1944 

 (no. 1833 pr. p.). Argetitine and neighbouring Islands: Berthelot Islands; on dioritic rocks; B.G.L.E., 

 18. iii. 1935 (nos. 1081-18, 1081-25, 1090. 1094-9. 1094-10, 1094-14, 1094-46, 1094-73, 1094-84, 

 1095-2). 



East Graham Land. Trinity Petiinsida, south coast: Hope Bay; near Boeckella Lake, altitude c. 

 60 m., on non-calcareous stones half submerged in a frozen shallow fresh-water pool; F.I.D.S., 

 15- iv. 1945 (no. 2363). 



The commonest Verrucaria in the Graham Land sector of the Antarctic. It is a very distinct species, 

 without obvious affinities. 



The thallus covers large continuous areas, and is not effigurate at periphery, but often bounded by 

 a very narrow whitish zone, inside which is a thin brown-blackish line. There is no dark hypothallus. 

 Thallus (in the typical condition) verrucose-areolate, with ± tumid and convex, irregularly obtusely 

 angulose areolae i •2-2-0 (-3-0) mm. diam., separated by deep, incised, pale-edged cracks about 0-15 mm. 

 wide; thickness varies between 0-3 and i-o mm. (rarely up to 2-5 mm.). Surface matt, smooth, not 

 pruinose, usually pale dull buff-brown (corresponding to pi. xlvi, 17"", 19"" and 2i""b in Ridgway, 

 1912), in less exposed positions paler, grey-brown with a slight pinkish tinge (Ridgeway, pi. xlvi, 

 ij""d, 21"" d), or in very shady positions grey-greenish (Ridgway, pi. xlvi, 21"" b-d). In certain places 

 where the thallus is subject to heavy inundation with water strongly impregnated with nitrogenous matter, 

 it takes on a red tinge (Ridgway, pi. xlvi, 13"" 6; exceptionally pi. xxxix, g"'a-b), either entirely or 

 in scattered spots and patches. In the normal brown state the thallus has a reddish brown cortex 9-15 /< 

 deep, composed of iso-diametric, thin-walled cells 3-4// diam., in many places overlaid by a hyaline 

 amorphous necrotic stratum 6-iOfi deep. Inpale-colouredspecimensthereisnodistinct cortex. Gonidial 

 algae tend to form more or less vertical groups or row^s extending through almost whole depth of thallus ; 

 bright green, subglobose or irregularly angulose, thin-walled, 6-9 fi diam. Fungal tissue between gonidia 

 hyaline, paraplectenchymatic, of thin-walled isodiametric cells 3-4/<diam. Lowermost 25-30 //of thallus 

 is without algae, hyaline, with vertically oblong cells. Perithecia numerous, but not present in all areolae 

 of thallus ; i-4(-5) in an areola, with the convex or almost hemispherical, brown-black, matt or slightly 

 shining apex (involucrellum) prominent above the surface and 0-2-0-3 mm. diam. Thallus not darkened 

 around perithecia. Ostiole usually visible under lens as a fine central pore. Excipulum immersed, globose, 

 290-345// diam., with colourless wall 30-35// thick formed of tangentially running hyphae I-5-2-0// 

 thick; at the apex, where it merges into the involucrellum, the excipular wall becomes brownish, 

 i The northern extremity of Hughes Bay, in future to be called Cape Sterneck. 



