LICHENS AND LICHEN. PARASITES

118 B.A.N.Z. ANTARCTIC RESEARCH EXPEDlTION
differentiation of parathecium, and the algae in vertical rows extend under the whole thecium,
actively dividing in cystococcoid colonies ; in 73140-26 two apothecia are contiguous, the parathecial
hyphae are not blackened where they come together, the thecium is only 150p tall, the spores eitber
very young or old and shrivelled. B140-24 clearly shows a proliferation of the paraphyses of an old
apothecium to form a new one, with still shrivelled ascospores between the old paraphgses.
Probably the algae are cystococcoid in all cases, but when not dividing it is difficult to distinguish
them from Protococcus. When the algal cells become more or less cylindrical from the pressure
of the medullary hyphae and are closely packed, they might easily be mistaken for l'rentepohlia
except for colour.
It is with some hesitation I have separated this species from Rhizocarpo?~ geographicum (Dill.
ex L.) Ram. in Lam. & DC. The thallns is milch thinner and smaller, the apothecia are smaller, the
disc is less convex, the paraphyses more slender and less closely septate, the asci are less ventricose,
and the ascospores are shorter and broader, making a considerably greater spore volume, although
the measurements fall within the range of R. geographicum as given by Vainio, Acta Soc. Fauna
F1. Fenn., 53,1,280-283; 1922. We have been unable to recognize the forms reported from our
region by other investigators, since more abundant material shows so many intergrading forms.
Material perhaps similar to that referred to R. geoyraphicum f. cyanales (Nyl.) Boist., Nouv. F1.
Lich., 2, 242; 1903 (Lecidea geographica f. cyanodes Nyl. in Gasilien, Act. Soc. Linn. Bordeaux,
53, 90; 1898) seems to be only moribund thalli. There is some variation in the closeness of the
assimilative areoles, so that extreme forms might possibly have been referred to R. yeographicunb
f. protothdlinwvh (Koerb) . Th. Fr., Lichenogr. Scand., 622 ; 1874 (R. geographicum v. atrovirens
f. protothullinum Koerb., Syst. Lich. Germ., 263 ; 1854) by Zahlbruckner, Deutsche Siidpolar Exp.,
8, 41; 1906. Most of our material would have been referred to R. yeoyraphicum f. contiguu?~
(Schaer.) Mass., Iticherch. Autonom. Lich. Crost. 100. 1852 (Lecidea geographica v. contigw
Schaer, Lich, Helv. Spicil., 3, 124; 1828, the forma typica of Dillenius' plate. R. geographicunb
f. atrovirens (L.) Mass., Nuov. Ann. Sci. Nat. Bologna, 7, 220; 1853 (Lichen atrovirens L., Sp. P1.
1141; 1753 etc.) reported by Bouly de Lesdain, Ann. Crypt. Exot., 4, 99 ; 1931 may belong here
but more probably to B. Johnstm. (see below).
On rocks with Verrucaria obfuscata, Thelidiunl praesalescens, Microglaena keryuelana,
Encephalographs ccrebrinella, ,l;ecanactis keryudmsis, Lacidea assentiens, L. Auberti, L. Eatoni,
L. intersita, L. phaeostma, L. rhkocarpiza, L. subdisjunguenda, L. subplana, Catillaria
keryuelensis, Rhizocarpon Mawsoni, Pertusaria cinerat%, P. subperrimosa, Aspicilia disjunguenda,
A. endochlora, A. lygomma, Lecanma atrocmsia, Pyrenodesmia vitellinelln, Buellia subplicata, B.
tristiuscula and Iiinudina aspiailina.
Kerguelen: Molloy Point, J. H. Kidder (U.S. Transit of Venus Exp., in ~uckerman Herb.,
sheet 3273 sub Buellia geographica) ; Royal Sound, B.A.N.Z.A.R.E. B90-4, B90-5, B90-7, B90-8,
B90-9, B90-10, B90-11, B126-11; Greenland Harbour, B.A.N.Z.A.R.E. B177-16, B177-31,
B17742, B17743, B17744; Observatory Bay, B.A.N.Z.A.R.E. B1924, B192-11, B192-36,
B192-37, B192-38, B192-67; Port Jeanne d'Arc, B.A.N.Z.A.R.E. B200-4; Murray Island,
B.A.N.Z.A.R.E. B210-1, B210-3 ; Mt. Wyville Thompson, 1,000-1,500 ft., B.A.N.Z.A.R.E. b246-7.
Heard Island : between Atlas Cove and Corinthian Bay, B.A.N.Z.A.R.E., B140-6, B140-9,
B140-13, ~140-14; B140-23, B140-24, B140-25, B140-26.
RHI~ARPON JOHNSTONI Dodge, sp. nov.
? Riuizocarpon geograpl~ict~w~
f. atrovirens Bouly de Lesd., Ann. Crypt. Exot., 4,99; 1931 non (L.)
Mass.
Type : Kerguelen, Greenland Harbour, B.A.N.Z.A.R.E. B177-39.