Thomson. — Plant-acclimatisation in Netv Zealand. 321 



worked in again, the subsoil was penetrated by the roots, 

 which decayed in it and thus helped to decompose and break 

 it up, and on such soil 50 and 60 bushels of wheat were taken 

 off per acre immediately after the thistle-crop. 



No doubt numerous other cases of the same kind could be 

 adduced, and it would be interesting to find out whether such 

 individual development anywhere tends to be maintained, 

 and, if so, whether it tends to the production of any perma- 

 nent variety. I think it possible that the development in the 

 past of such large species of plants as Myosotidium nobile, 

 Aciphylla squarrosa and A. colensoi, Ranunculus lyallii y 

 Ligitstictim latifolium, and Pleurophyllum criniferum, all of 

 which are giants as compared with their nearest relations, 

 is due in great part to their isolation in these Islands, and 

 the comparative absence of severe competition. 



Another curious change which has been noticed as taking 

 place is the adaptability of some of our indigenous plants to 

 the changed conditions brought about by settlement. Some 

 of the native species appear to be able to hold their own, and 

 even to benefit by these altered circumstances. I have al- 

 ready recorded the fact that, with the increase of blackbirds 

 and thrushes, many succulent-fruited plants have become 

 widely dispersed. This is true of native as well as of intro- 

 duced species. Fuchsias are increasing, not diminishing, in 

 numbers in the Town Belt, and in my garden I find a species 

 of Coprosma (C. robusta) and the common cabbage-tree 

 (Cordyline australis) coming up where none were sown, and 

 where I do not remember any growing naturally for some 

 twenty-five years. The fruit of the latter is often eaten by 

 starlings, and thus distributed. Again, some creeping plants- 

 furnished with rooting stems or underground stolons are able 

 to spread in cultivated ground and in pasture. I have noticed, 

 three species particularly aggressive — viz., Epilobium nummic- 

 larifoliiim, Hydrocotyle asiatica, and H. muscosa* 



Note. — In "Darwinism," p. 29, 2nd edition, 1889, Wallace 

 quotes W. T. L. Travers, and, apparently on his authority, states 

 that "the most noxious weed in New Zealand appears, how- 

 ever, to be the Hypochcerix radicata, a coarse yellow-floweredt 

 composite not uncommon in our meadows and waste places. 

 This has been introduced with grass-seeds from England, and 

 is very destructive. It is stated that excellent pasture was in 

 three years destroyed by this weed, which absolutely displaced 

 every other plant on the ground. It grows in every kind of 

 soil, and is said even to drive out the white-clover, which is- 



* The Rav. A. Don, Chinese missionary, states that Raoulia australis 

 is greatly on the increase in the interior of Otago. It is one of the few. 

 plants which is noc being eaten out by rabbits. 

 21 



