LICHENS AND LICHEN. PARASITES

DODGE-LICHENS AND LICHEN PABASITES 251
of loose, irregular hyphae, basal layer of scattered, dark, isodiametric cells ; assimilative thallus
of distinct lobes up to 1.75 mm., irregular, often dichotomously branched, radiately cracked,
becoming diffused and scattered toward the centre, white to yellowish or grey, margins usually
lighter in colour; cortex fastigiate, breaking away over the tops of the areoles; algal layer 6OP
thick, cells 14-16~, scattered, protococcoid; medulla 35-40p thick, of loosely woven hyphae; basal
layer not well (developed, occasionally represented by a few dark cells.
Apothecia up to 0.6 mm. in diameter, irreguarly hemispheric, sessile on the areole, black,
parathecium of thick-walled pseudoparenchyma; hypothecium up to 5OP thick; thecium 60-70p
tall ; paraphyses 1-l-Sp, expanding to 2~ at the tips with heavy black incrustations, branched or
unbranched, epithecium about lop, dark ; asci 36-46 X 14-16~) long clavate, thick-walled, 8-spored ;
a.:.cospores 10-13.5 X 5-5-7~, bilocular-ith or without constriction of the septum, blunt or
slightly tapering.
Our material is scant, but agrees with the type in microscopic characters, although somewhat
less radiate. It seems to have a strong affinity for the mica of the granite, and spreads only slightly
over the other constituents. The thallus is rather old and weathered.
King George V Land : Cape Denison, near hut, B.A.N.Z.A.R.E. 536-58.
BU~IA PERNIQRA Darb.
Buellia pernigra Darb., Jour. Bot. Brit. For., 61, 106 ; fig. 1, 2 ; 1923.
Type : South Victoria Land, Mt. Erebus (British Antarctic (Shackleton) Exp.)
Thallus crustose, subeffigurate, about 1 cm. in diameter, arealate, thinner and flatter toward
the margin, areoles tall and rounded toward the centre, black and somewhat shining, about 225p
thick; o(lter amorphous layer variable in thickness (about 25~) ; cortex 25-35p thick, fastigiate, of
coarse, thick-walled hyphae, the upper cells aubspherical, very thick-walled and blackened, giving
the colour to the thallus ; algal layer of cystococcoid colonies, about 3 5 in ~ diameter, sometimes
closely packed and nearly filling the thallus, sometimes more scattered and confined to the upper
half; medulla of closely woven hyphae, 3-4p in diameter, thin-walled, becoming vertical and'
passing into the carbonaceous lower cortex or hypothallus, which is 35-4OP thick.
Apothecia semi-immersed to subsessile, margins somewhat prominent, smooth, black, disc plane
to slightly convex, black; parathecium 50-90p thick, carbonaceous, pseudoparenchymatous, not
/ extending below the hypothecium; hypothecinm hyaline to slightly brownish, not sharply different
tiated from the medullary hyphae but more compact and pseudoparenchymatous; thecinm about
100~ tall, not sharply differentiated from the hypothecium below; paraphyses relatively coarse,
repeatedly dichotomous, terminal cells broadly clavate, 4-6~ in diameter, united into a carbonaceous
epithecium 2OP thick ; asci ellipsoidal, tips slightly thickened when young, disappearing early,
relatively numerous in proportion to the paraphyses, 8-spored; ascospores ellipsoid, 2-celled,
dark brown, soon very black, up to 14-15 X 7-Btc, mostly somewhat smaller, constricted at the
septum, relatively thin-walled.
Spermogonia immersed in the thallus, flask-shaped, wall black, about 18p thick, with fastigiate
slender hyphae (like a miniature cortex) ; spermatiophores 10-12 X lp, septate, once dichotomous
above; spermatia ellipsoidal, about 3 X 0.5p.
On rock with Umbilicaria rugosa.
King George V Land : Cape Denison, B.A.N.Z.A.R.E. 536-23, 536-60.
t,