SYSTEMATIC ACCOUNT 23 



Genus Staurothele Norman 

 1853, P- 240. 

 Staurothele gelida (Hook. f. and Tayl.) M. Lamb, n.comb. (Fig. T,j, k) 

 Verrucaria gelida Hooker and Taylor, 1844, p. 639. 



' Verrucaria umbrina' in Hooker, 1845-7, P- 54i) P'- cxcviii, fig. iv (non Wahlenberg). 

 Verrucaria umbrina var. monospora Nylander, 1855, p. 175. 

 Verrucaria monospora Malme, 1928, p. 9. 



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

 altitude c. 7 m., on vertical south-facing side of basalt dyke; F.LD.S., 28. xii. 1944 (no. 2125); near 

 summit of islet, on old limpet shells; F.LD.S., 28. xii. 1944 (no. 2101). Argefitine and neighbouring 

 Islands: Berthelot Islands; on north-facing inland cliflp (non-calcareous); B.G.L.E., 18. iii. 1935 

 (nos. 1081-32, 1094-91). 



East Graham Land. Croivn Prince Giistav Channel: Station 30 ; west side of island, on agglomerate 

 rocks in slope just above sea-level; F.LD.S., 12. xi. 1945 (no. 2841 pr. p.). Corry Island^; on agglo- 

 merate outcrop near sea-level at foot of scree slope; F.LD.S., 17. xi. 1945 (no. 2835 pr. p.). Persson 

 Island; north-west shore, at sea-level, on non-calcareous stones; F.LD.S., 21. xii. 1945 (nos. 2663, 

 2664). James Ross Island: St. 51 ; altitude c. 60 m., on basaltic stones irrigated in summer by snowmelt 

 water; F.LD.S., 23. xi. 1945 (nos. 2640, 2641 pr. p., 26^2 pr. p.). Cape Lachmann; altitudes. 30 m., on 

 non-calcareous stones near a fresh-water pond; F.LD.S., 21. xi. 1945 (no. 2673); altitude c. 60 m., on 

 basaltic rock; F.LD.S., 21. xi. 1945 (no. 2781). Seymour Island: western slopes of plateau in north 

 part of island, altitude c. 150 m., on a calcareous stone; F.LD.S., 30. viii. 1945 (no. 2477 /)r. p.). 



Like St. clopima (Wbg.) Th. Fr., but spores constantly single in ascus and usually larger than in 

 St. clopima: (45-)6o-75 x (i5-)2i-32// (or up to 90// long, in Argentine specimens according to 

 Malme, loc. cit.). 



The holotype of ' Verrucaria gelida ' from Cockburn Island in the Erebus and Terror Gulf was located 

 in the herbarium of Churchill Babington, now in the British Museum. In outward appearance it is 

 quite similar to Staurothele clopima, and like that species has bacilliform hymenial gonidia. Single- 

 spored asci are occasionally met with in St. clopima, but the uniformity of the character in all our 

 Antarctic material seems to justify the specific separation suggested by Malme. 



In external morphology the range of variation is like that of St. clopima, that is to say, large. The 

 thallus may be reduced and scanty, consisting of a thin crust between the perithecial warts (as in the 

 Cockburn Island holotype) or up to i mm. thick and verrucose-areolate. In the former case a ring of 

 gonidia-bearing thallus tissue is often carried up and isolated on the sides of the perithecium (Fig. i;). 

 The colour of the thallus varies with exposure, from a medium brown (Ridgway, 1912, pi. xlvi, 

 13""^) in shaded south-facing positions, to brown-black (Ridgway, pi. xlvi, 17"" «) in some cases on 

 exposed stones (no. 2673). The excipulum is more or less globose, variable in size (200-300// diam.), 

 colourless or almost so when young, but becoming increasingly brown with age, until, in old perithecia, 

 it consists entirely of dark brown tissue hardly distinguishable from the apical brown-blackish involu- 

 crellum. The hymenial gonidia are cubical to bacillar, 3-9 < 2-5-3 -o//, P^le green. Thalline gonidia 

 bright green, iglobose, thin-walled, 6-o-io-5// diam. 



Hooker's illustration in the Flora Antarctica shows the single spores still enclosed in the ascus. 



Like St. clopima, St. gelida is particularly characteristic of positions seasonally inundated by fresh- 

 water rivulets, in this case derived from the melting of snow and ice. One finds it on lowlying ground 

 with good snow cover throughout the winter, and where during the heavy thaws of spring and early 

 summer it leads a purely aquatic existence. Its maximal development was seen on James Ross Island 



1 Formerly Cape Corry. 



