34 Transactions. 



on both sides with alpine forms o£ Senecio, DraccjpJiyllum, Veronica, Oaxil- 

 theria, Pimelia, etc., amongst the shrubs, and of Cehnisia, grasses, sedges, 

 etc., amongst the herbaceous plants. This is certainly a somewhat extreme 

 case, 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, Asplenittm hooherianum, and 

 Hymenopliyllum 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 every^vhere 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 occur in the mountain 

 districts, that any great number of varieties are found. 



In such valleys and gullies we see clumjDS 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 tJie plants of each species, however, 

 presenting a perfect identity in general appearance and stnictiire, or, at aU 

 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 



