BUCHANAN.— Sketch of the Botany of Otago. 189 
the economy of nature, by raising the land and making it fit for the growth 
of superior plants, the ground being soon taken possession of by Phormium 
tenax and other shrubs. These raupo-fringed lagoons are the favourite 
haunts of ducks. 
The Phormium tenax is abundant in this district, where it finds good soil 
and moisture, so essential to its full development. Areas are also covered 
by the fern Pteris aquilina var. esculenta, growing in some places six feet 
high. The tutu (Coriaria ruscifolia) is abundant on the Lower Clutha: it 
is generally found in gullies, where it finds the deepest soil for its large 
ramifying roots. 
Perhaps the most striking plant of the district is the cabbage-tree (Cor- 
dyline australis). It is abundantly scattered over the ridges, having, from 
its non-inflammable nature, escaped burning. Ridges dotted with cabbage- 
trees, and filled in between with the graceful plumose toitoi grass (Arundo 
conspicua), present one of the most singular features in New Zealand vege- 
tation 
The grasses are numerous in species and of good kinds, and the con- 
ditions of sufficient heat and moisture, with good soil, being present, the 
pasture is superior. 
From the Tuapeka to the junction of the Manuherikia, eighty miles, the 
river is more or less closed in by mountains, with forest on the slopes and 
scrub on the flats, although considerable portions are now burned and under 
88. 
At the junction of the Manuherikia River with the Clutha, the country 
opens out into a large, terraced, ancient lake basin, through which the 
Clutha River runs from its leaving the Dunstan Gorge, twelve miles. Over 
this large distriet the country is open grass, and, when first visited, of a 
remarkably sparse growth, consisting of three species on the terraces, but 
richer in the small valleys. A little scrub was at that time found on the 
banks of the Manuherikia, chiefly Olearia virgata. The parehing winds 
and light dry soil of these interior basins must have always been an obstacle 
to a luxuriant vegetation, and from the same causes, they would be con- 
tinually liable to be cleared by fire. 
The river passes fifteen miles through the Dunstan Gorge, hemmed in on 
each side by the mountains, with a narrow terrace on both sides. The slopes 
of the mountains here are steep, but carry a good pasture of numerous 
species of grass. 
At the termination of the gorge, upwards, the Clutha is joined by the 
Kawarau River, and the country opens out again into another ancient lake 
basin, fringed by terraces, and stretching forty-five miles to the Wanaka and 
Hawea Lakes. The whole of this district is similar to the last, with poor 
