LICHENS AND LICHEN. PARASITES

DODGE-LICHENS AND LIOHEN PARASITES 173
Thallus in small cerebriform cushions up to 5 mm. in diameter and 4 mm. tall; surface somewhat
rugose, marginal lobes flattened, smooth, margin minutely crenulate, paler, Dresden brown:
nearly covered by apothecia; cortex 3540p thick, somewhat decomposed, appareutly a pseudoparenchyma
from periclinal hyphae 4-5p in diameter, heavily incrusted with small yellowish brown,
minute crystals and including small rock crystals ; algae forming a dense layer below the hypothecium,
scattered cells in the medulla, cells 7-8p in diameter, spherical or angnlar, protococcoid;
medulla compactly woven, of thick-walled, hyaline hyphae about 4p in diameter.
Apothecia 5-6 mm. in diameter, disc flat to somewhat convex, isabelline to brownish olive,
margin thin, lighter, soon disappearing, not elevated ; sessile, constricted at the base ; amphithecial
cortex similar to that of the thallus but more decomposed; algal layer about 55,~ thick, of densely
packed cells filling the space between the cortex and thecium; parathecium about 35p thick below
the hypothecium, of densely woven, more or less periclinal hyphae, almost devoid of protoplasts
in the mature apothecium, 4-5p in diameter; hypothecium about 20p thick, of subvertical, slender,
closely septate, deeply staining hyphae ; thecium 50-55p tall ; paraphyses slender, about thrice
dichotomously branched above the asci, branches moniliform above, terminal cell ellipsoidal about
6 X 4p, thick-walled, encrusted with dark crystals; asci clavate, 22-25 X 7-8p on stalk about 25p
long when maturing spores, tips thickened, protoplast mamillate, becoming more ellipsoid about
20 X 12p as spores mature; ascospores unicellular, hyaline with thick epispore, 8-10 X 4-5p.
What seems to be a young state of L. Johnstoni occurs on a worn rock of fine grained granite
from Cape Denison and a small thallus from Madigan Nunatak. The thallus is only slightly
developed, with a single stalked apothecium. In the apothecium sectioned, the structure is similar
to this species, but the dimensions are slightly smaller, the spores being only 7-8 X 4p. AS these
apothecia have developed in the shade of Umbilicaria subcerebriformis, perhaps the development
has been suppressed, or it may be only a juvenile state. Some of the material is associated with
Buellia sp.
On rocks with Lecidea cancrifomis, Charcotia cerebriforntis, Lecanora exsulans f. ntinor and
Rinodina f rigida.
King George V Land: Madigan Nunatak, ca. 2,400 ft., 30 miles east of winter quarters,
C. F. Laseron, A. A. E. 25-5; Cape Denison, A.A.E. 45, 50-1, 130, 161, 162, 163, 164, 165, 166,
177, B.A.N.Z.A.R.E. 536-14, 536-32, 536-34 type, 536-35, 536-36, 536-37.
Queen Mary Land: Hippo Nunatak, C. T. I-Iarrisson, A. A. E. 65-2.
LECANORA MCLEANI Dodge, sp. nov.
Type: King George V Land : Horn (Dreadnought) Bluff, A. L. McLean, A.A.E. 47.
Thallus umbilicatus, polyphyllus (sed foliolis plus minusve ~onc~escentibus) in pulvinulos
applanatoi, plicatos, cerebriformes, fere apotheciis tectos, partes inter apothecia melleae, partes
umbrosae et superficies inferior fulva, subrugosa ; cortex superior ca. 20p, laxe fastigiatus, hyphis
viridibus, ea. 4p diametro, cellulis isodiametricis, strato hyalino gelifacto 10-12p tecta, ex hyphis
tenuissimis periclinalibus ; stratum algarum 354OP crassitudine, altera parte continuum, altera
parte coloniis discretis, sphaericis, cellulis cystococcoideis, &lop diametro ; medulla laxe contexta,
hyphis 2p diametro, in partibus laxioribus ad 5-6p, ramosis, anastomosantibusque ; cortex inferior
fastigiata, hyphis verticalibus ramosis, anastomosantibus in stratum gelifactum, 40-60p crasstitudine,
sine rhizinis.
Apothecia substipitata, disco plano, cinnamomeo-rufo, mox nigricans, dein irregulariter
expanso, convexo, frequenter in acervulis cerebriformibus et superficiem superiorem thalli tegentia ;
Gphithecium ab structura thalli non distincturn; stratum algarum sub parathecio continuum;