34 Transactions. 
on both sides with alpine forms of Senecio, Dracophyllum, Veronica, Gaul- 
theria, Pimelia, etc., amongst the shrubs, and of Celmisia, grasses, sedges, 
etc., amongst the herbaceous plants. This is certainly a somewhat extreme 
ease, and I only quote it in order to show within what narrow limits large 
differences may exist in the climatal and other conditions to which the same 
plants may be exposed. Besides being so much broken, these mountain 
ranges are usually very steep, and their flanks are furrowed by innumerable 
streams. Land slips are frequent, and indeed every facility exists for the 
transport, not only of seeds, but also of growing plants from higher to lower 
levels. 
It may easily be understood that these peculiarities in the mountain 
chains referred to give rise, all over the region, to great variations of soil 
and climate, and (putting out of the question the extreme case above 
quoted) the differences in these respects which are ordinarily observed 
between the northern and southern slopes rising from valleys having an east 
and west course, and the eastern and western slopes of valleys running 
north and south, are very great indeed. The Hurunui Valley, for example, 
runs nearly east and west, and whilst on the one side there is a comparatively 
rich vegetation, including, in the wooded gullies up to two thousand five 
hundred feet, such ferns as Lomaria vulcanica, Asplenium hookerianum, and 
Hymenophyllum scabrum, on the other side, at the distance of only a 
mile or so, far below this altitude, we find nothing but stunted alpine 
growth. 
As I have before observed, the Veronicas especially have a very wide 
range, both lateral and ascending, sundry forms of this plant being found 
all over the Middle Island from sea level up to great altitudes. I find that 
the purely alpine forms at alpine elevations vary very little indeed, preserv- 
ing everywhere an almost perfect similarity in their prominent prevalent 
characters. I find, moreover, that those species which affect low altitudes 
vary also but little, and that in fact it is only in the intermediate zone, 
amongst the innumerable gullies and valleys which oceur in the mountain 
districts, that any great number of varieties are found. 
In such valleys and gullies we see clumps of Veronicas sometimes up- 
wards of an acre in extent, at times composed of but one species, and at 
others consisting of several species, all the plants of each species, however, 
presenting a perfect identity in general appearance and structure, or, at all 
_events, only exhibiting such small anomalies as constantly occur in the 
separate plants of any dominant species, without the necessity of supposing 
them to result from hybridization. 
_ Moreover, each of the several species thus found in society, will also be 
found growing separately in widely distant localities which happen to 
