LICHENS AND LICHEN. PARASITES

DODGE--LICHENS AND LICHEN PARASITES 151
lacerate and irregular, or even microphylline from regeneration of broken lobes, minutely rimose
areolate (giving almost exactly the appearance of the surface of Elaphyomyces muricatus) ; drab,
shading to hair brown or darker; lower surface smooth to subverrucose, mostly black, sometimes
wood brown at the margin without rhizinae ; outer gel of dead cells nearly amorphous, quite variable
in thickness, up to 25p; cortex variable in thickness, 25-55p, the outer 15-1BP deep brown,
fastigiate, less clearly so below, hyphae 5-6p in diameter, cells nearly isodiametric with ve1.p
thick'walls; algal layer about 35p thick, compact, protococcoid, cells 8-lop in diameter, spherical
or angular from mutual pressure; medulla about 165p thick, hyphae predominantly periclinal,
about 4p in ,diameter, from moderately compact to relatively lax and arachnoid; lower cortex
about 35p thick, the innk 25p very compact and subfastigiate, the outer lop black or very dark
brown, cells subspherical, B 7 p in; diameter.
Apothecia lecanorine, about 0.2 mm. in diameter, disc concave, black, slightly rough, margin
/
slightly elevated (especially in younger apothecia) ; arhphithecial cortex 20-35p thick, of the same
structure as the thalline cortex but darker, medulla 20-45p thick, similar to that of the thallus but
rather looser, including single algal cells, many apparently dying or dead (not staining well with
eosin or phloxine) ; parathecium 15-20p thick, carbonaceous, of dark brown hyphae about 4p in
diameter, becoming 35-40p thick below the hypothecium and somewhat more loosely woven; hypothecium
hyaline, about 25p thick, of slender, subvertical hyphae; thecium about 35p tall;
paraphyses slender, terminal cell clavate, blackened, cutting off a spherical cell about 4p in
diameter ; asci thick-walled, 25-30 X 10-12p, broadly clavate, 8-spored ; ascospores hyaline,
2-celled, one cell somewhat larger than the other, slender with somewhat pointed end, rounding to
ellipsoid as it matures, 8-10 X 4-5p.
Spermogonia immersed, flask-shaped to subconic (starting as an oblate sphaeroid in the algal
layer, and expanding through the cortex until the ostiole is finally exposed) ; wall 10-12p thick,
of dark brown, isodiametric cells; spermatiophores 10-12 X 2p, septate, moniliform, occasionally
branched; spe matia cylindric, ends truncate, about 4 X 0.6~. After it has ceased to function,
it fills with L ick-walled brownish, little branched, moniliform hyphae with isodiametric cells'
about 4p in diameter. In the thallus in which new apothecia were proliferating from the old
thecium a new spermogunium developed just below the ostiole of the old one.
As some of our material is more mature than the type, we have based the above description on
B.A.N.Z.A.R.E. 536-15. A re-examination of the type for the young stages of apothecial formatioy,
shows a dense tangle of slender hyphae ill the lower part of the algal layer which expands
; i
u&ard between the algae which are stimulated to rapid division. The young parathecium is very
: ' tdin and hyaline and is surrounded by a thick algal layer forming the amphithecium. The
expanding apothecium ruptures the cortex and pushes it back, forming a stalk about as tall as the
disc is wide. Then the parathecium blackens, ruptures above and fuses with the thalline cortex.
The algal layer continues to surround the sides_ of the parathecium in all the material from Marie
Byrd Land. As the asci mature, the algae gradually die out in the amphithecium. No suggestion
of parasitism was seen at any stage.
On rocks with Lecanora exslllans, L. Johnstoni and Hudlia frigicla.
King George V Land : Cape Denison, J. G. Hunter, A.A.E. 3,4,42-1, 48,49, 67, 102-2, 103-1,
124, 140, 141, 142, 144, 1,049-1; B.A.N.Z.A.R.E. 536-13, 536-14, 536-15.
Queen Mary Land : Alligator Nunatak, C. T. Harrisson, A.A.E. 28-1, 58 ; Possession Nunatak.
C. T. Harrisson, A.A.E. 62-1 ; Hippo Nunatak, C. T. Harrison, A.A.E. 64.