NARRATIVE OF THE CRUISE. 375 



largeness of the area where snow constantly accumulates and cannot be melted, no doubt 

 accounts to a considerable extent for the peculiar conditions in Heard Island. A similar 

 rapid descent of the snow-line within a few degrees of latitude occurs in the Chilian 

 Andes, 1 so great is the cooling influence of the vast Southern Ocean. Heard Island is in 

 a corresponding latitude to Lincoln ; possibly when England was in its last glacial epoch 

 Heard Island enjoyed a much milder climate, and it was probably then that the large trees 

 grew, the trunks of which are now fossil in Kerguelen Island, and that the ancestors of 

 Lyallia and Prutglea flourished. 



A stretch of land on the northwest side of the plain was covered pretty thickly 

 with green, which on closer examination was seen to be composed of patches of Azorella 

 growing on the summits of mud or sand hummocks, separated from one another by 

 ditches or cavities, of usually bare brown mud. Some of these Azorella patches were of 

 considerable extent, and the plant was evidently flourishing and in full fruit. On some 

 hummocks grew tufts of the grass, Poa cookii, in full flower and with the anthers fully 

 developed ; and on the sheltered banks the Kerguelen. Cabbage (Pringlea aiitiworbutica) 

 grew in considerable quantity, but dwarfed in comparison with Kerguelen specimens, both 

 in foliage and in the length of the fruiting stems. Most of it was in fruit, but some still 

 in Mower, as at Kerguelen Island. Around pools of water in the hollows grew a variety 

 of a British plant, Callitriche verna (var. obtusangula), in quantity, and it occurred also in 

 abundance submerged, in company with a Conferva, In the same sheltered spots grew 

 Colobanthus kerguelensis, in greater abundance even than at Kerguelen Island. These 

 five flowering plants,-' all occurring also in Kerguelen Island, were the only ones found in 

 the island, and it is improbable that any others grow there. Heard Island has thus a 

 miserably poor flora, even for the higher latitudes of the southern hemisphere. The 

 Falkland Islands, in lat. 51° to 52° S., have one hundred and nineteen phanerogamic 

 plants, and Hermit Island, far to the south of Heard Island, in lat. 56° S., has eighty-four 

 phanerogams, and amongst them trees which there reach their southern limit. 



About the sides of the hummocks already described grew scantily four species of 

 Mosses, one of which (Grimmia I Schistidium] insularis, Mitt.) proved to be new and 

 peculiar to the island. The greater part of the land surface of Heard Island free from 

 ice, besides the green tract described, is entirely devoid of vegetation. Only on the talus 

 slopes of the hills on their sheltered sides, are seen scattered in a very few places scanty 

 patches of green. These, composed mainly of Azorella, stretching up the slopes, terminate 

 at an elevation of a few hundred feet in bright yellow patches, which are composed of 

 Mosses just as at Marion Island on the high slopes. lichens were, searched for in vain. 



At Corinthian Bay large masses of seaweeds were banked up on the sandy shore ; 



1 Qrisebaoh, Die Vegetation der Erde, Bd. ii. p. 407, Leipzig, 1872 ; Darwin, Journal of Researches during the 

 Voyage of H.M.S. "Beagle," p. 244, ed. 1879. 



2 Professor Oliver, F.B.S., Journ. Linn. Soc. Land., vol. xiv. p. 389, 1875. 



