210 BEPOET— 1891. 



grasses {Aclphylla sqiiarrosa and colensoi) in many parts of 

 Otago. Grazing animals do not touch these plants, and it 

 cannot be due to pigs rooting them out, for wild pigs are not 

 common now compared to what they were thirty years ago. 

 The only explanation I can suggest is that the pistillate flowers 

 frequently fail to be fertilised. This I know sometimes happens. 

 No one has ever recorded what insects fertilise these flowers, 

 and the question is now complicated by the disappearance of 

 insects formerly common, and the abundance of introduced 

 forms. 



Some indigenous plants seem quite able to hold their own, 

 under favourable conditions, against introduced forms. Thus, 

 in poor pastures near Dunedin, which have been ploughed and 

 sown down in English grasses, and where only cattle feed, 

 Haloragis micrantha, Hydrocotyle asiatica, and other species 

 of the genus, Wahlenbergia gracilis, Nertera setulosa, and 

 other small plants abound and form great part of the sward. 

 All these plants, however, and indeed most others which I 

 have found in similar situations, and which show a similar 

 power of holding their own, are not peculiar to New Zealand, 

 but have a wide range outside these Islands. They really, 

 therefore, are species which have already undergone a very 

 severe struggle for existence, and, as shown by their wide 

 geographical distribution, have come victoriously out of it. On 

 the other hand, where neither cattle nor sheep are allowed to 

 graze — in such localities, e.g., as the Town Belt in Dunedin — 

 I find that, while shrubs like manuka {Lcptospermum) , Bubus, 

 Coriaria, Cassinia, various scrubby species of Coprosma, &c., 

 are able to hold their own, there are very few of the smaller 

 plants which can resist the encroachment of the introduced 

 grasses, especially cocksfoot, dogstail, and sweet -vernal grass. 

 Even in such places, however, a few species — e.g., Celmisia 

 longifolia — can hold their own, while, wherever the ground is 

 damp, species of Banunculus, Einlohiwn, Anthericum, &c., 

 can succeed. This is, no doubt, because few or no marsh 

 plants have been introduced. 



As regards insects which seem to have benefited by the intro- 

 duction of new forms of plants and animals, there is almost no 

 evidence yet collected. I am inclined to think, however, that 

 a few forms have increased decidedly since the settlement of 

 the colony began. Thus the curiously banded and spotted 

 black-and-white moth, Nyctemera annulata, seems to be more 

 abundant than of yore. Its larva has taken to feeding on the 

 introduced groundsel (Senecio vulgaris), and on a very glabrous 

 ivy-leaved geranium {Pelargotmnn sp.), on either of which 

 plants it may be found in spring in great abundance. Many 

 of the solitary bees of the genus Lamprocolletes seem to be 

 increasing in numbers with the increase of introduced yellow- 



