LICHENS AND LICHEN. PARASITES

258 B.A.N.Z. ANTARCTIC RESEARCH EXPEDITION
formantibus. Apothecia 0-1-0.2, rare 0.3 mm. diametro, disco plano, nigro, margine laevi, albido
dein obscure griseo nigricantive; amphithecium ca. 8OP crassitudine, cortici thallino similis cum
seriebus algarum inter hyphas; parathecium non evolutum; hypothecium non bene distinctum:
thecium 110-150~ altitudine; paraphyses tenuissimae, super ascos dichotomae, apicibus non
incrassatis; asci clavati, apicibus incrassatis, 55 X 15p, evanescentes; ascosporae subdistichae,
brunneae nigricantes, ellipsoideae, pachydermeis, 22-29 X 8-llp.
Thallus obscured by apothecia, reduced to a small squamule, about 0.7 mm. in diameter and
0.2 mm. thick, prolonged below into a short stipe about 200p long and 125p in diameter, where brown
hyphae 4-5~ in diameter, either singly or in small rhizinciad fascicles attach the thallus to the moss;
cortex fastigiate, pseudoparenchymatous, 3OP thick, more or less decomposed and brownish in the
stipe, up to 55p thick, hyaline with very thick walls and septa in the squamule ; algae cystococcoid,
cells 8-15~ in diameter, dying out in the stipe, sometimes nearly filling the medulla, but tending to
disappear below and penetrate the cortex at the margin of the squamule and between the apothecia
(preparatory to forming new apothecia?), tending totdisappear under the centre of the apothecium ;
medulla of thick-walled, closely woven hyphae with small air spaces, sometimes more periclinal
under the hypothecium but not differentiated as a parathecium.
Apothecia 0.1-0.2 mm., rarely 0.3 mm. in diameter, disc plane, black, margin smooth, white
becoming dirty grey and blackening, closely paclred over the squamule but not deformed or angular ;
amphithecium about 8OP thick, similar in structure to the thalline cortex with rows of algae between
the hyphae, outermost a.1ga.l cell of each row surrounded by a single layer of cortical hyphae; para.
thecium not differentiated ; hypothecium indistinct, slender branches of medullary hyphae apparently
passing upward directly into the more deeply staining paraphyses, the asci arising from short
branches of deeply staining hyphae periclinal to the base of the thecium ; thecium 110-l5Or~ tall ;
paraphyses very slender, dichotomously branched above the asci, tips not thickened, ending in the
darlr brown epithecial gel when young, finally cutting off spherical cells about 3p in diameter ; asci
clavate with a thickened tip and rounded protoplast when young, about 50 X 1 5 as ~ the ascospores
begin to assume a brownish colour, then apparently disappearing while the spores still develop in
the thecial gel ; ascospores subdistichous, brown becoming black, ellipsoiclal, with very thick walls
and septum, protoplasts hemispheric, connected by a very slender isthmus, the wall thinning and
the isthmus disappearing, the protoplast ceasing to stain as the wall darkens, until finally the spore
is slightly constricted at the septum, the ends somewhat pointed, straight or slightly curved,
22-29 X 8-llp. As is often the case with large, dark ellipsoidal spores, the greater lengths are
associated with the smaller transverse diameters, making the spore volume more nearly constant
than the linear dimensions seem to indicate.
This species seems closely related to R. egentissima Hue from Petermann Island (Graham
Land Archipelago). It has the same habit and habitat, but with a much thicker thalline cortex,
smaller apothecia, margin not crenulate, without parathecium, taller thecium and smaller asco
spores. As in R. eyentissima, the proportion of asci to paraphyses is unusually large. As our
material is very scant, 1 have not sacrificed any of it to learn if the apothecia arise directly from the
moss plant without forming a basal squamule. While the basal portion of the moss is dead, the
tips seem to have been alive when collected, and project between the quamules as if the fungus
portion of the lichen was parasitic or saprophytrc on the moss and derived part of its nutrition
from the moss, accounting for the great reduction of the thallus.
Growing over mosses with Nostm, etc.
King George V Land: Cape Denison, McKellar Islets, A. L. McLean, A.A.E. 90-2.
Queen Mary Land : Hippo Nunatak, C. T. Harrisson, A.A.E. 78-2, type.