LICHENS AND LICHEN. PARASITES

152 D.A.N.Z. AKTARCTIC RESEARCII EXPEDITIOX
Derntatiscunr Nyl., Bot. Zeitg., 25, 133 ; 1867.
DERMATISCTJM Nyl.
Type : Lichen I'hunberyii Ach. (L. viridis L. f.).
Thallus monophyllous, attached to substrate by central hapteron, ~vithout rhizinae; heteromerous;
upper cortex fastigiate, pseudoparellchymatous; algae Trentepoltlia; medulla loosely
woven; lower cortex fastigiate, darlr. Apothecia immersed at first then sessile, disc finally somewhat
convex, not gyrose; amphithecinm present; parathecium present but not highly developed;
hypothecium hyaliile or slightly brownish ; paraphyses slender with thickened tips, not branched;
asci clavate, 8-spored ; ascospores 2-locular, brown. Spermogonia immersed in small warts, wall
very thin, hyaline, spermatiophores little branched, iiot septate; spermatia fusiform cylindric,
straight.
This rare genus is lri10\~11 oiily from one species in South Carolina, one (or perhaps two) from
the Cape of Good Hope and Madagascar, and the two here described from King George V Land and
Queen Mary Land. The nature of the algae were not mentioned in the early descriptions, but Hue,
Bull. Soc. Bot. Prance, 62,13; 1915 reports Trentepohlia in material from Madagascar and I have
found the same in a portion of the type of D. cutawbense Nyl. from South Carolina and in our two
new ones.
D~MATISCUM MAWWNI Dodge, sp. nov.
Type : King George V Land, Cape Denison, B.A.N.Z.A.R.E. 536.
Thallus 7-8 mm. diametro, obscure grisea, rugosa, margine minute lobato; cortex superior ca.
75p crassitudine, parte dimidia superiori gelifacta, inferiori fastigiata, pseudoparenchymatica,
cellulis leptodermeis ; stratum algarum ad 75p crassitudine, cellulis compactis vel coloniis parvis vel
filamentis singulis brevibus Trentepohlioideis, ad 7-aP diametro, cellulis breviter cylindricis;
medulla ca. lOOp crassitudine, hyphis plus minusve periclinalibus, leptodermeis, dense contextis ;
cortex inferior 35p crasstitudine, brunneus, fastigiatus. Apothecia 0.2-0.3 mm. diametro, nigra,
erumpentia, maturitate circiter lOOp elevatis, disco convexo, nigro ; parathecium 2OP crassitudiiie,
hyphis tenuibus, conglutinatis, periclinalibus, exteris obscuris (nbi super corticem projectae),
reliquis hyalinis ; hypothecium centro 90p crassitudine, ad marginem tenuescens, hyphis verticalibus,
inferis subbrunneis ; thecium ca. 90p altitudine ; paraphyses tenues, 1. 5-2p diametro, septatae,
apicibus clavatis, 2-locularibus, 4r. diametro; asci late clavati, apicibus incrassatis, protoplasto
mamillato, 40 X 12p stipite ca. 35p longitudine; ascosporae subdistichae, 2-loculares, obscure
brunneae, 11-15 X 7-8p, septo subconstrictae.
Thallus 7-8 mm. in diameter, dark gray, rugose, margin of minute, rounded lobes, appressed
to the surface of the rock but attached by a hapteron, without rhizinae; upper cortex about 75p
thick, the upper half slightly gelified ; correspoiiding to the amorphous layer of Umbilicaria, the
lower half fastigiate, of thin-walled pseudoparenchyma, the outer cells of the inner half darkened
in the vicinity of apothecia; algal layer very variable from 75p thick in a compact mass' of cells,
to small colonies and single cells, apparently Trentepohlioid, of short filaments, up to 7-8p in
diameter, cells short cylindric ; medulla about lOOp thick, very compact, of more or less periclinal,
slender, thin-wallex hyphae; lower cortex brownish, abut 35p thick, fastigiate, of coarser, brown
hyphae.
Apothecia 0.2-0.3 mm. in diameter, black, erumpent and only slightly elevated at maturity
(about loop), disc convex, black ; parathecium 20p thick, of slender, conglutinate, periclinal hyphae,
the outer ones darkened where they project above the amphithecial cortex, otherwise hyaline;
hypothecium 90p thick in the centre thinning toward the margin, of vertical, deeply staining hyphae,