Nov. 1899.] BOTANICAL SOCIETY OF EDINBURGH 257 



1896. In the first three months of 1897, the Gums do 

 not seem to have suffered at all from locusts, but Pines and 

 Blackwoods evidently did. Oaks, Paraisos, and Poplars are 

 almost stationary ; and Eobinia at first decreases, and then 

 gi'ows a little. 



Thus part of the poor growth of 18 96 and 1897 must 

 be laid to the account of the locusts, and not all to 

 weather. 



I am informed that the locusts spared Melons, Cucumbers, 

 Paraiso trees, and Cottonwoods {Populus angvlata). This 

 growth-curve diagram certainly shows that Paraisos 

 sympathised with other trees during the locust invasion ; 

 and the Cottonwood also, at least in January and 

 February 1897, when its growth was 1 millimetre against 

 the nine-year January average of 9*4 millimetres, and 

 -1 millimetre against the average 5*9 millimetres for 

 February. 



This was the worst invasion of locusts known in 

 Uruguay since, if I remember rightly, the year 1856. I 

 am told : " Not only have they eaten the leaves of the 

 trees, with the exception of the two kinds, but also the 

 bark of the topmost branches, even of the Orange trees ; so 

 much so, that the plantations look white." The water in 

 the streams went bad with their dead bodies. The danger 

 arising from this was fortunately removed by a cloud-burst, 

 which Hushed the streams. 



In the " Notes on Tree Measurements " published in 

 1890, the decrease in growth at a certain season of 

 deciduous trees was commented on at considerable length. 

 Further experience fully coniirms the remarks then made, 

 but distributes the season of decreases over a longer space 

 of time. 



It is worthy of remark tliat during the first five of the 

 fourteen years 1885-1898, the evergreens grew 2*942 

 millimetres, or 47 per cent, of their total growth for 

 fourteen years; and 3'319 millimetres, or 53 per cent, of 

 their total growth in the last nine years. But the seven 

 deciduous trees grew in the first five year 3-276 millimetres, 

 or 55*5 per cent.; and in the last nine, 2-627 millimetres, 

 or 44'5 per cent, of the total growth for fourteen years. 

 What might be called the " par " rate of growth, if weather- 



