LICHENS AND LICHEN. PARASITES

DODGE-LICHENS AND LICHEN PARASITES 149
Thallus monophyllous, 8-9 cm. in diameter, upper surface deeply and coarsely reticulatescrobiculate,
folds closer and pits shallower near the margin, centre deep olive buff, margins dark
olive grey, crenulate, very thin and fragile, not laciniate; below black, dull, minutely pruinose,
smooth, without rhizinae, not folded at the umbilicus; upper cortex 10-15p thick, of large isodiametric
cells, very dark on the outside, hyaline within, covered by a layer of dark cells up to 25r thick ;
algal layer 20-65p thick, cells up to lop in diameter, protococcoid ; medulla 200-300p thick, of thickwalled
hyphae 2-4p in diameter, with rather short cells, loosely interwoven, branched and
anastomosed ; lower cortex up to 40p thick, pseudoparenchymatous, almost black.
Apothecia up to 2 mm. in diameter,
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irregular, gyrose, fuscous to black, dull ; parathccium up to
25p thick, fuscous, cells isodiametric, thick-walled, continuous laterally with the thalline cortex;
medulla of loosely woven hyhpae ; hypothecium wp '6 150p thick, dark, irregular ; thecium 50-80p
tall; paraphyses lp in diameter, expanding to heads 1.5-2p, straight or branched, septate,
epithecium 10-13p thick, gelified, brown; asci 37-46 X 11-13.5p, clavate above and very slender
below, with a thin sheath, 8-spored; ascospores 7.5-9 X 3-44 ellipsoidal, mostly with blunt ends,
hyaline.
Our material is sterile and smaller (most specimens have been broken, so that it is difficult to
decide how large the original specimens were). M'icroscopically they agree well in thalline
characters, the upper cortex being a little thicker and the lower a little thinner than in the type.
The lower cortex is always thicker than the upper cortex of the same thallus and there is no compact
layer of medulla next the lower cortex. Hunter 11-1 shows old spermogonia about 130p tall
and about 150p in diameter, wall pseudoparenchymatous, 10-15p thick, brown, darker above.
On rocks with Dmatiscum Mawsomi, Lecanora ezsularn and its f. minor, Alectoria congesta,
Bzlellia frigida and B. pernigra.
South Victoria fiand : McMurdo Sound, Ross Island, D. Mawson 1,056 (First Shackleton
Exp.) ; Cape R O ~ ~ Mawson ~ D . 1,058 (First Shackleton Exp.).
King George V Land : Cape Denison, J. G. Hunter 8,ll-1,22, A.A.E. 145,146, B.A.N.Z.A.R.E.
536-23, 536-24.
Queen Mary Land : David Island C. T. Harrison, A.A.E. 57; Hippo Nunatak, C. T. Harrisson,
A.A.E. 64.
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UMBILICARIA SUBCEREBRIM)RMIS Dodge, sp. nov.
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: ,!l'yye : George V Land, Cape Denison, J. G. Hunter, A.A.E. 70.
Thallus monophyllus, 2 cm. diametro vel major, superficie superiori rugosa vel cerebriformi,
margine laevi vel subcrenato, subpruinosus, centro avellaneo vel oliveaceo dein nigricante, super-
ficie inferiori nigra, opaca, subrugosa et minute verrucosa ad marginem, sine rhizinis; stratum
amorphum tenue, ad 15p vel deest ; cortex superior ca. 30p crassitudine, fastigiatis, hyphis 5-6p
diametro, lumine lp, insuper cellulis isodiametricis in strato 10-15p crassitudine ; stratum algarum
ca. 30p crassitudine, cellulis protococcoideis ad 8p diametro, sparsis aut in parvis coloniis dispositis;
medulla crassitudine variabilii, laxissime contexta, hyphis hyalinis 6-7p diametro, lumine 1-2p,
strato infero 15-25p crassitudine, hyphis periclinalibus 3-5p diametro, densissime contextis ; cortex
inferior fastigiatus, brunneus, ca. 18p crassitudine, cellulis 5-6p diametro, isodiametricis vel sub-
ellipsoideis. Apothecia spermogoniaque non visa.
Thallus monophyllous, 2 cm. in diameter (perhaps larger as the specimens are broken), surface
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rugose to cerebriform, deeply folded, appearing almost polyphgllous but not so, margin smooth or
somewhat crenate (edges mostly broken), subpruinose, centre wood brown shading to olive brown,
finally blackening; lower surface black, dull, slightly rugose and minutely verrucose toward the
margin, without rhizinae; layer of dead cells thin, 15p thick or even absent; upper cortex about