LICHENS AND LICHEN. PARASITES

DODGE--LICETENS AND LICHEN PARASITES 17
referred to a species described from St. Paul Island to the north, but Nylander's description is
so brief that I cannot be sure without seeing the type. The central and western portions with
their highlands and mountains have not been explored botanically. The presence on the low
eastern mountains of species not found at lower levels, suggests that exploration of the highlands
below the snow line would yield many more specie$, particularly in the genus Usnea, section
Roccellinae, which is at present unknown from the Crozet group, with a single collection from
Marion Island, relatively seldom collected on the south-eastern mountains of Kerguelen and
abundant in the B.A.N.Z.A.R.E. collections from Heard Island.
HEARD ISLAND. Aubert de la Rue (1930a) has given a brief history of exploration and
account of the geography. Glqciers cover the whole of the north-western end except a narrow
border of cliffs. East of this a low sandy area extends across the island, where the only
botanical collections have been made. To the south-east Mt. Andree Aubert de la Rue, 170 m. is a
volcano from which the western side of the erater has been eroded by the sea. Mt. Drygalski
(225 6.) to the east has sand up to 50 m., Amrella extending up to 100 m. and only mosses above.
From this point the land rises to Big Ben Peak with perpetual snow about 200-300 m. Old sealers
state the temperature from March to December is below zero Centigrade, the summer mean about
3" C. and the mean annual about -lo C. Acaena, so common on Kerguelen, was not found.
The seven volcanoes are subsequent to glaciation which covered the island. The rocks seem
younger than those of Kerguelen (Subert de la Rue, 1929) but no specimens of clear stratigraphic
importance were collected. Rogers Peak and Red Island are the most recent volcanoes,
Mt. AndrCe Aubert de la Rue and Mt. Drygalski are older. No traces of activity of Big Ben Peak
were noted, although Lt. Hobart Seymour of the "Wakefield" reported clouds of smoke in 1910.
The Deutsche Siidpolar Expedition made a short visit, collecting two species of lichens. If
Aubert de la Rue made collections they have not been reported on. The B.A.N.Z.A.R.E. collected
31 families, 20 genera and 34 species. The families are all found in IZerguelen, but four of the
families not found in the Crozet Group are characteristic of somewhat cooler regions than the
four families of;'ihe Crozet Group not found in Heard [sland. Six species are at present
endemic to Heard Island, probably of little significance as three of the species are inconspicuous
and easily overlooked in collecting and the other three are in Usnea, sect. Roccellinae, which
probably will be found in the higher elevations of Kerguelen, perhaps already represented in
Eaton's (British Venlis Transit Exp.) collections in the British Museum, but unavailable to me
at present.
Al1,khe evidence so far available for Rergudia, points to a very old lichen flora with five
endefr;ic genera and one genus having a distantly related species in the Auckland Islands. The
Phyllopyreniaceae has one genus in Kerguelen and one in Fnegia, each with a single species.
~he~~astodiaceae has a single species in Kerguelen, one in Macquarie Island, one in MacRobertson
Land, various species in the Graham Land Archipelago, South Georgia and from Fuegia
northward in very high alpine regions to Alaska and across Bering Strait to north-eastern
Siberia. In most of the larger genera, the species are more closely related to each other than
they are to species from other regions. In very rare cases, there are suggestions of distant
relationships with species in the mountains of South Africa and of Australia.
The origin of the flora is a difficult problem, for which the various theories proposed are
briefly reviewed by Aubert de la Rue (1932, 214-216). None of the classical methods of transport
give a clue. Only a single species of Mastoclia suggests a relationship with Antarctica,
the nearest continent, or with Macquarie Island, the ~~esternmost island of the New Zealand
Plateau, with a climate no more severe than Heard Island. The distantly related species of
A~gopsis, one each in Alickland Island and Kerplielia and Pertrisnria perrinlosn of New Zealand