Otago Institute. 447 
Mr. G. M. Thomson's list would soon be doubled ; but some of the plants on 
that list he thought should be considered as New Zealand plants, such as 
Polygonum aviculare and Sonchus oleraceus. He had noticed in and near the 
rivers in Canterbury Nasturtium amphibium and Anacharis alsinastrum ; 
these plants spread from America and Southern Europe into Northern Europe 
in exactly the same way. Most of these plants, he thought, would continue ; 
and even the injurious ones would be more difficult to keep down by cultivation 
than they were in Europe, on account of good climate. With reference to the 
appearance and disappearance of thistles, he remarked that in Sweden, when 
the forest is cut down and burnt, Geranium bohemicum appears, no one knows 
whence ; but in a few years it disappears, and never comes again. In the 
same way, when land is first broken up for cultivation, it comes, but soon goes 
again. 
Captain Hutton exhibited a collection of Hepatice made by Mr. Kirk and 
himself on the Great Barrier Island. 
Dr. Berggren remarked that the difference was very small between them 
and those that he had found in the South Island. In many of the New 
Zealand genera the development is not known, and the structure has not been 
studied ; but when this is done it will throw great light on the classification of 
the order. He referred particularly to Petalophyllum, Steetzia, and Symphogyna. 
Captain Hutton exhibited a sea trout (Salmo trutta) caught in Otago 
Harbour, and stated that another had been recently caught. 
Mr. Webb stated that Mr. Young, of Palmerston, had informed him that 
140 sea trout, hatched from Tasmanian ova, were turned into his pond early in 
1871, of which about 120 were let into the river in 1872, and there could be 
no doubt that these were some of that lot. 
