260 JOURNAL OF SCIENCF. 



The Disappearance of Spear-Grass- — It is well known that the 

 large species of Spear-grass ( 'Aciphylla ) are rapidly disappearing in all 

 parts of Otago, and it is very probable that this once common and 

 characteristic element in the native vegetation of the district will soon 

 become as rare as it was formerly abundant. The causes of this change 

 in the prevailing vegetation of large trusts of country seem to merit 

 some consideration. It might be thought that plants naturally so 

 admirably defended against the attacks of herbivorous animals would 

 be practically exempt from their ravages All kinds of stock eat the 

 foliage readily enough, but the larger animals are for the most part 

 prevented from indulging any liking for it. by the habit of growth of 

 the plants and the dense array of sharp points that meet their lips and 

 tongue. Rabbits however are not so easily repelled, for owing to the 

 small size of their heads they can attack single leaflets while keeping 

 clear of those standing near them. Accordingly spear-grass plants are 

 eaten by them more or less at all seasons, but especially during the 

 winter and in elevated situations where snow lies on the ground for 

 considerable periods In such stations the plants suffer very seriously 

 from their attacks, and in many extensive districts have been already 

 all but exterminated. As a rule the leaves are eaten right back to the 

 ground and the plants die off at once. In lower situations the rabbits 

 are not so troublesome, but even there the disappearance of the plants, 

 though less rapid and complete, is going on steadily and surely. 1 do 

 not know to what age the life of a spear-grass plant may extend, but it 

 can hardly exceed fifteen or twenty years. In that time we may 

 suppose that all the well-established plants will die off from old age. 

 Seeds are produced as a rule in great abundance, but in spite of this 

 the number of young plants that may be observed growing up is very 

 limited, and in ground that is well stocked and closely cropped hardly 

 any are to be seen. On the other hand if a patch of land is securely 

 fenced against cattle and sheep great numbers of plants of all ages are 

 to be found. This may be very well seen in the somewhat extensive 

 railway enclosures in the valley of Manuka Creek on the Lawrence 

 branch railway line. Within this enclosure plants of Aciphylla 

 squarrosa of all ages abound, and easily hold their own against all 

 competitors in the struggle for existence. Outside the railway fences 

 on the other hand plants of any age are extremely rare, even on land 

 that has never been touche 1 by cultivation, and seedlings are hardly to 

 be met with anywhere. Rabbits are not very plentiful in this district, 

 and the disappearance of the spear-grass cannot in any way be attributed 

 to their interference. Everything goes to shew that as the old plants 

 die off, the young ones are not suffered to grow up to take their place. 

 This is most likely due to the fact that cattle and sheep readily eat up 

 the tender and less pungent, rigid, an 1 compact leaves of the young 

 plants. There cannot, I think, be any doubt that stock readily eat the 

 foliage when they can attack it without danger from the prickles, and 

 this they can easily do when the plants are in the seedling state. The 

 rapid disappearance of spear-grass therefore, seems due in the lowlands 

 to cattle and sheep eating up the tender seedlings, and in the higher 

 and bleaker situations to the attacks of rabbits, more especially in the 

 winter season. In rabbit infested country of considerable elevation, the 



