Rutland. — The Fall of the Leaf. Ill 



climatic conditions stamped so plainly on the surrounding 

 vegetation that even the most incurious cannot fail to notice 

 them. 



That plants cease to grow or increase in volume when the 

 temperature of the air and soil fall below a certain point is 

 too well known to require more than mention ; but the degree 

 of cold at which growth ceases varies extremely when many 

 species are observed. For instance, some plants grow only 

 during the warm summer months ; others, again, lie dormant 

 during that season, as many of our cultivated bulbs, putting 

 forth their leaves and flowers in autumn, in spring, and even 

 in winter. 



That there is a degree of cold which will put each species 

 to rest, and another which would terminate its existence, may, 

 I think, be safely assumed. Between these two effects — the 

 suspension of growth, and death — other effects — the fail of the 

 leaf, and the destruction of the overground portion or ascend- 

 ing axis of the plant — sometimes take place. 



Evidently some species are incapable of exhibiting the last- 

 mentioned phenomena, death immediately following the sus- 

 pension of growth. 



Taking again our former examples — the laurustinus and the 

 guelder-rose — we commonly see those shrubs gi'owing together 

 in our gardens, the former in full leaf when the latter is quite 

 bare. A further diminution of temperature, instead of assimi- 

 lating the appearance of these species, would destroy the 

 lamaistinus, leaving the guelder-rose uninjured. 



We thus arrive at the conclusion that the evergreen habit 

 may be absolute or conditional ; and, secondly, that, though a 

 species may remain unaltered when exposed to a temperature 

 which deprives others of their leaves, the latter may be the 

 hardier, or capable of surviving through the greatest degree of 

 cold. 



Of the absolute and conditional evergreens this district 

 furnishes some instructive examples. Thus, the Olearia 

 hectori,'-' evergreen in other parts of the colony, is a deciduous 

 shrub in the Pelorus Valley, where it grows in low situations 

 outside the bush, associated with Plagianthus betuUnus, So- 

 phora tetraptera, and Fuchsia colensoi, which are also de- 

 ciduous. 



Again, along the shores of the Pelorus Sound the karaka 

 {Corynocarpus IcBvigatus) is very plentiful ; but, finding that it 

 did not occur in the inland valleys, I some years ago raised 

 plants from seed, which were immediately cut to the ground 

 by the first severe fi'ost, and thus destroyed. In this case the 



* For the identification of this and many other species I am in- 

 debted to the kindness of Mr. T. Kirk, F.L.S. 



