LICHENS AND LICHEN. PARASITES

168 B.A.N.Z. ANTARCTIC RESEARCH EXPEDITION
Lecullora Ach., Lichenogr. Univ., 77; 1810.
LECANORA Ach.
Type: Acharius treated 132 species in 1810 and 139 i11 1814. During the riilleteeiith century,
the name was applied to species with lecailorine apothecia now placed in various families besides
the Lecanoraceae. Thirty-six of Acharius' original species are still placed in Lecunora sect.
Ezslecanora as understood by modern authors.
Thallus crustose, uniform, attached to the substrate by the hyphae of the hypothallus or of the
medulla, without rhizinae, heteromerous ; ecorticate or corticate ; algae protococcoid. Apothecia
sessile, circular; ampitheci~un well developed; parathecium usually absent or inconspicuous;
hypothecium hyaline ; asci normally 8-spored (rarely 16-32-spored) ; ascospores hyaline, ellipsoidal,
elongate to spherical, rarely reniform, relatively thin-walled without a sheath. Spermatia
exobasidial, bacilliform, cylindric or filiform, straight or curved.
This very large genus of nearly world wide distribution is rather poorly represented in our
area. While I am inclined to restrict it to the section Eulecanora, and recognize the placodioid
forms as a separate genus, as many have done previously, there are so many problems of nomen-
clature and part of the pertinent literature is not available to me, I have left them in Lecanora for
the present.
LECANORA ATRQCAESIA Nyl.
Lecanora atrocaesia Nyl. ap. Crombie, Jour. Bot. Brit. For., 13, 334; 1875: 15, 101; 1877: Jour.
Linn. Soc. Bot., 15, 185 ; 1876 : Phil. Trans. Roy. Soc. [London], 168, 49 ; 1879 : Rept. Sci.
Results Voy. "Challenger" Bot., 1,2,235 ; 1885 : Zahlbr., Deutsche Siidpolar Exp., 8,47 ; 1906 :
Bouly de Lesdain, Ann. Cryptog. Exot., 4, 100; 1931.
Lecanora a2bocaeru2escens Bab. ap. Hook., Cryptog. Antarct., 232 ; 1845 : F1. Antarct., 2,538 ; 1847
non Ach.
Type: Kerguelen, Observatory Bay and Volage Bay, A. E. Eaton (Venus Transit Exp.).
L. a2bocaeru2escens Bab. based on material from Christmas Harbour, J. D. Hoolrer (Voy. "Erebus
& Terror ' ') .
Thallns 400p or more thick, rimose areolate, determinate, marginal areoles somewhat lobate,
thick, on a black hypothallus; cortex about 60p thick, a palisade of vertical hyphae about 3p in
diameter, the upper 20p disintegrating into a more or less structureless gel; algal layer about
20OP thick, protococcoid, cells 718p in diameter, occurring singly or in more or less vertical
rows separated by strands of vertical hyphae, loosely interwoven; medulla bf inore or lees
vertical hyphae similar to those of the cortex but more loosely woven. Apothecia innate in thalline
areoles which become elevated above the others ; discs plane, blaclr, becoming convex ; amphitheciunl
not differentiated except as the thallus cracks around the apothecium, leaving a layer of thallus
about 15&180p thick around and under the apothecium ; parathecium about 75p thick, thiniiirig at
the top of the thecium, of densely tangled, large, brownish hyphae, but not carbonaceous; hypothecim
lenticular, 18OP or less thick in the centre, of hyaline, slender, deeply staining hyphae,
becoming subvertical above and not sharply differentiated from the thecium which is about
75-90p tall; paraphyses coarse, septate, 4-5p in diameter, unbranched, thin-walled and densely
staining at first, becoming brownish with highly gelified walls, cutting off a large, spherical, thiclrwalled
brown cell at the tip ; asci cylindric, becoming narrowly clavate, tip thickened, protoplast
truncate or with a small umbo, 8-spored; ascospores hyaline, unicellular, with moderately thick
wall, 8-13 X 5-6p.