Aston. — Vegetation of Tarawera Mountains. 305 



mountain prior to that event. He states that forests composed of large 

 trees grew upon the sides of the Tarawera Mountain, and these, of course, 

 were wholly wrecked by the eruption. Those on the site of the chasm dis- 

 appeared altogether. Fortunately, T. Kirk had ascended the mountain in 

 1872, and his pubUshed papers (1 and 27) make it plain that where favourable 

 to plant-Hfe the surface of the mountain was clothed with vegetation, though 

 on the highest parts it was scanty and stunted. A dwarf shrubby vegetation 

 was found on the very summit of Tarawera, in sheltered places affording 

 cover for a luxuriant growth of mosses ard lichens, in which the orchids 

 Caladenia hifolia, Thelymitra longifoUa, and Orthoceras Solandri occurred. 

 Elsewhere on the summit were Metrosideros hypericijolia, Corokia bnddleoides, 

 Coprosma lucida, Olearia furfuracea, Raoidia tenuicaidis, Dracophyllmn 

 strictum, D. Urvilleanum, Polypodium serpens, Tniesipteris tannensis ; while 

 near the summit were noticed Lycopodium voliibile (2,800 ft.), Astelia trinervia 

 (3,300 ft.), Cyathodes empetrijolia, and Gaultheria oppositijolia (3,200 ft.). 



On the margins of Tarawera Lake Kirk noticed abundant trees of Metro- 

 sideros tomentosa of large size, and also Astelia Cunninghamii, Scirpus 

 maritimus, Ranunculus acaulis, and Ghenopodimn glaucum var. ambigwim. 

 At the entrance to the gorge separating Ruawahia from Wahanga were 

 observed large terrestrial specimens of Metrosideros robusta, and elsewhere 

 he saw Panax Colensoi, the most prominent shrub, forming handsome dwarf 

 bushes sheltering HyvienopJiyllum bivalve, H. multifidum, and other ferns ; 

 Danthonia sp., Dcyeuxia quadriseta, and Pittosporum tenuijolium were also 

 observed. He states that the total number of species collected above 

 3,000 ft. did not exceed seventy, and consideied that the vegetation of the 

 mountain comprised a remarkably limited number of species.* 



It would be too much to assume that all vegetation was entirely killed 

 out at the base of the mountain by the eruption of 1886. The dead stumps 

 of large Metrosideros tomentosa trees may still be found standing at the lake- 

 side, and many species of the family Myrtaceae are so tenacious of life that 

 stumps with several feet of mud or scoria round them might have sprouted 

 and produced seed. Moreover, seed might have become uncovered by the 

 rain cutting gulches in the soft mud and sand, and have found the absence 

 of competition from other plants a factor favourable to growth. 



Thus, on account of the volcanic origin of Tarawera Mountain and the 

 isolated position of the north-west face, the foot of which, save for one narrow 

 isthmus, is washed by the waters of Lakes Rotomahana and Tarawera, 

 and on account of the eruption of 1886, this area presents peculiar facility 

 for the study of the spread of species on new ground, since only an in- 

 finitesmal fraction of the plants could have survived the 1886 eruption. f 



The North-west Face. 



In the spring of 1913 the author twice visited Tarawera, on the first 

 occasion (14th September) ascending to the summit of the range by the 



* Kirk instances other sea-littoral plants, such as Convolvulus Soldanella, Juncus 

 maritimus var. australiensis, Leptocarpus simplex, Carex pumila, Zoysia pungens, and 

 Bromus arenarius, which are found in this thermal district, as supporting the theory 

 of the submarine origin of the lowlands of the central portion of the North Island; 

 but when one considers that wild water-fowl, such as shags, black swans, and wild duck, 

 travel frequently between coast and lakes, and that shags nest in the Metrosideros 

 tomentosa trees on the coast, a simpler explanation of the presence of these sea-littoral 

 plants in fresh-water littoral situations far inland becomes apparent. 



t A lithographed reproduction of a photo of Tarawera seen from the south-west 

 before the eriiption, in A. P. W. Thomas's report [loc. cit.), shows dense forest to 

 about one-third of the height above Lake Tarawera. 



