LICHENS AND LICHEN. PARASITES

B.A.X.Z. ANTARCTIC BESEARCII ESPEDI'rJON
USNEA SCABRIDULA (Lamb), Dodge, comb. nov.
Neuropogon acronaelamus v. imcti.u.vw f. scabridulz~s Lamb, Jour. Linn. Soc. Bot;, 52, 220 ; 1939.
Type: Antarctic, probably Ross Sea region, in Brit. Mus., not seen. The following description
based on George V Land, Cape Denison, Commonwealth Bay, D. Mawson, A.A.E., 1,049.
Thallus 3 cm. tall, branching essentially dichotomous, but often one branch larger than the
other, and internodes variable, giving the appearance of irregular branching; branches not
divergent, curved, ascending, rigid, ultimate branches relatively short and coarse, fragile;
chamois to cream buff, only the ultimate branches black maculate or wholly blackened, primary
branches rarely slightly rugose with annular cracks, not blackened, slightly constricted at the
base, secondary branches not constricjed, mostly closely papillate with large, round, eroded
soralia; 0.7-0.8 mm. in diameter, containing pale yellow, granular soredia; the ultimate branches
less sorediose and there the soredia are much smaller, cortex about 75-8OP thick, highly gelified,
a palisade of very thick-walled, conglutinate hyphae, the outer 2OP nubilated with very small
crystals, giving a brownish appearance in section, the rest hyaline; medulla K-, dense, 90-110~ -
thick, the outer 35,~ filled with algae in a nearly continuous layer, with a few scattered cells
below, algal cells protococcoid, 10-12p in diameter, the rest of the medulla of interwoven hyphae
,about 4~ in diameter, not leaving conspicuous air spaces, slightly looser next the axis,
here producing a fracture plane when roughly handled; chondroid axis 200 X 370,~ elliptic
in cross section, of slender, conglutinate, longitudinal hyphae.
The papillae seem to function as breathing pores, being provided with a slender tube throngh
the cortex, more or less filled with crystals. No spermogonia nor apothecia seen.
When first seen this species appeared to be related to U. g.radifera (Vain.) Motyka, but
microscopically it seems closer to U. fasciata Torrey, agreeing in general proportions and in the
elliptic cross section of the axis. Our plant may prove to be a sorediose variety of that species.
U. acromelanu is much more remote in habit, nature of the soredia and black-edged cracks and
lacks the characteristic papillae of our plants although the proportions of cortex, medulla and
axis are similar.
South Victoria Land: Cape Irizar [75" 30' S., ca. 163" E.] D. Mawson, 1,057-2, British
Antarctic Exp., 1907-9, growing with U. antarctica.
George V Land: Horn [Dreadnought] Bluff [ca. 68" 25' S., 149" 45' E.] -4. L. McLean,
A.A.E. 46; Cape Denison, on gneiss, Commonwealth Bag [67" S., 142" 36' E.] J. G. Hunter,
A.A.E. 19, 45; D. Mawson, 1,049; Sta. 88, B.A.N.Z.A.R.E. 536-38.
USNU SUBPAPILLATA Dodge, sp. nov.
Type: Queen Mary Land, Hippo Nunatak, C. T. Harrisson, A.A.E. 82-3.
Thallus 2-3 cm. altitudine, subdichotome ramosus, rami non late divergentes, adscendentes,
rigidi, lutei, ramis ultimis brevibus, nigris; ramis primariis infra laevibus, non fractis, basi non
constrictis, subrugosis vel subfoveolatis, superne cum papillis minutis sparsis ; soralia minutissima,
subronvexa, in ramis ultimis, raro in axi conflnentia, soredia granulosa subflavida, non conspicue
erosa; cortex 60-65p crassitudine, strato, extero 2Jp gelifacto, hyaline hyphis verticalibus cum
cellulis isodiametricis, crystallis minutis acicularibus flavidis nubilatis; medulla K-, 1OOp crassi-
tudine, hyphis dense contextis; algae cellulis ca. lop diametro, singulis vel in coloniis parvis in
parte tertia medullae irregulariter dispositae: axis chondroideus 250p diametro, teres vel sub-
hexogonus in sectione transversali, hyphis tenuibus conglutinatis, longitudinalibus, pachyderma-
ticis. Apothecia spermogoniaque non visa.