I io ANNALS OF SCOTTISH NATURAL HISTORY 



in any other work with which I am acquainted dealing with 

 the arctic regions.) It is therefore indicative of a mild and 

 equable climate, and I believe its presence may be taken 

 as fairly conclusive that the climate of the period was at 

 least in no degree more boreal than at the present time. 



A somewhat special interest attaches to the three species 

 of Thuidium. T. tamariscinum is, of course, one of our 

 commonest and most widely-spread woodland mosses. But 

 the case is quite different with the other two. Until 1874 

 T. delicatulum was not recognised as a European moss, 

 though abundant in North America. In that year Lindberg 

 detected and recorded it from a single station in Finland. 

 Six years later Philibert found it in France, and subsequently 

 it has been discovered to be widely spread over the European 

 continent, though apparently not very common, and chiefly 

 in the lower montane regions. It was unrecognised as a 

 British moss until 1885, when it was recorded by Holt from 

 Tyn-y-groes, North Wales ; while in 1889, Binstead gathered 

 it in fruit at Lodore. Since that time its recorded distribu- 

 tion has been greatly extended, and it is entered in the 

 "Census Catalogue of British Mosses" (1907) from 17 vice- 

 counties in England, Wales, and Scotland (besides four 

 doubtful records), and 6 in Ireland. Of the former, 7 are 

 Scotch, 5 Welsh ; and of the 5 English, 3 are on the west 

 coast, the Isle of Wight and west Yorkshire being the 

 remaining ones. It will be seen, therefore, that its distribu- 

 tion with us is exclusively western and montane. It is, in 

 fact, almost entirely a rupestral plant, though occurring 

 occasionally on sandy debris by mountain stream and lake 

 sides. I have only once found it elsewhere, in a bog at 

 the foot of a Perthshire mountain, and then looking very 

 unhappy and unlike itself. 



Thuidium Philiberti has a somewhat similar history, 

 though it is a still more recently recognised member of our 

 moss flora. It was described from France as a new species 

 (T. intermedium'} by Philibert in 1893, but the name had 

 already been preoccupied by Mitten, and Limpricht renamed 

 it as T. Philiberti in 1895. It was then known from several 

 localities in Central Europe and North America. I had 

 gathered it on Craig Chailleach, Perthshire, in 1893, but had 



