DISCOVERY REPORTS 



(no. 2640), where it formed a conspicuous association on flat stones lying in extensive rivulets and 

 seepage areas derived from an ice cap higher up. 



Geographical Distribution. Outside the Graham Land sector of the Antarctic, this species is 

 known from Argentina and Chile. It and St. chpima are perhaps bipolar-vicarious species. 



Genus Microglaena Korber, 1855 

 Microglaena antarctica M. Lamb, n.sp. (Fig. 3/); PL IV, fig. 5) 



South Shetlands. Nelson Island: Harmony Cove, on fine-grained non-calcareous rock; Discovery 

 10^-^-=; 14 xii 1934 (nos. 1480--1, 1480-2, the latter the holotype). Deception Island: east coast, by 

 Ringed Penguin rookery, on agglomerate rock ;B.G.L.E., 16.1. i936(no. 1381^3); tuff cliffs above mam 

 Ringed Penguin rookery, altitude c. 140 m.; B.G.L.E., 20. i. 1936 (nos. 

 1399-4, 1400-13, 1400-38); south-west side of 'Neptune's Bellows', on 

 weathered agglomerate crags with fair sheker; Discovery 1933-5. lo- '■ 

 1935 (nos. 1488-1, 1488-2 pr. p.). Desolation Island: on non-calcareous 

 rocks in gull rookery, altitude c. 20 m. ; Discovery 1933-5. §• i- ^935 

 (no. 1487-6). 



Description. Thallus cnistaceus, imiformis, plagulas irregidares 0-4-2-5 p.^ ^ Microglaena antarctica 

 centim. latas inter alios lichenes formans, primo areolatus, mox verrncoso- M. Lamb. Spores. 



areolatus aut congeste verrucosus, ad i (-2) mm. crassus, albidus vel impure 



albidus vel sordtde ebttrneus, opacus, epruinosus; areolae seu verrucae o-3-i-o mm. dtam., rotrmdatae 

 angulosaeve, planae aut convexae, saepe convoluto-tuherculatae. Hypothallus nullus dMus; soredm 

 etisidia desunt. Gonidia cystococcoidea, globosa, 4-5-i5-o/^ diam., pallide aut sat laete vmdta, 

 pariete tenui Perithecia singulatim verrucis thallinis o-5-i-o mm. latis insidentia, thallo obducta, apice 

 denudato fusconigricanti, ostiolo punctiformi, minuto, saepe levtter papUlato. Excipulum rmmersrm 

 globosum 450-520/. diam., omnino incolorattm, stiperne involucrello fusconigncantt, latenbus hand vel 

 parum producto obtectum. Paraphyses persistentes, filiformes, haud ramoso-connexae, i •0-1-5/^ crassae, 

 sinuosae, in aqua facile separandae. Asci clavati, 135-210 ■: 30-4° /^ pariet^ ^^colorato yo-T5M crasso. 

 Sporae ^-nirarius S)nae in asco, uni- aut partim biseriatim dispositae, oblongo-elhpsotdeae aut elhpsotdeo- 

 fusiformae, muriformi-cellulosae {cellulis numerosis a^boideis), incoloratae vel levissime mfuscatae halone 

 nullo indutae,formammagnitudinemquehaudpmdlumvariantes, 42-90 < 13-35 li,plerumquearc. 60 x 25 /.. 

 Pycnidia verrucis thallinis immersa, ostiolo nigricanti punctiformi o-i-o-3 mm. diam.; Jycnocomdia 

 filiformia, curvata rectave, 1 5-24 >< 0-6-0-8 /.. Thalhts extr^ et intus KHO- ../ sordrde fiavofr^scescens , 

 CaCl O,- CfiHiNH,)^-, I- ; sporae plasmaque ascorum I+rubroftdvescentes. 



There is no basal hypothalline layer, the thallus being attached to the substratum by the hyphae of 

 the lower medulla. Thallus corticate; cortex colourless, 15-34/' thick, of ±rounded, thm-walled cells 

 2-C-5-0/. diam., in places crushed and indistinct. Gonidial stratum 60-250/. deep, sometimes entirely 

 filling the verrucose areolae; the algae in the lower parts of the thallus are often dead and brown. 

 Medulla colourless, hyaline, composed of much branched and intricated hyphae i-5-3-o// thick. Ihe 

 brown-black apex (involucrellum) of the perithecia is 0-2-0-5 mm. diam., matt or shming, with central, 

 often lighter coloured ostiole. Excipulum colourless or with a faint yellowish tinge formed of com- 

 pacted tangentially running hyphae about i /. thick. Involucrellum consists of dark-walled cells 

 3-5/. diam., merging ±gradually into the surrounding colourless tissue. No hymemal gonidia. 

 Paraphyses about the same length as the asci, not capitate; septa visible after treatment with KHO 

 HCl and I, 9-18/. apart. Walls of asci not laminated, I-, with a thinner spot at the apex. Pycmdial 

 fulcra exobasidial, simple, 9-13 < 1-0-1-5/.. 



