110 TRANSACTIONS AND PROCEEDINGS OF THE [Szss, 1x1. 
the cold of the climate, the lichens followed the retreating 
ice and snow into the hills and the Arctic and Antarctic 
regions. 
We find further evidence for this when we compare the 
most highly developed and therefore oldest lichens with the 
lower and therefore more recent forms, in regard to their 
distribution in the Arctic and Alpine zones. Of the Green- 
land fruticulose lichens 5°5 per cent. alone are unknown in 
Germany, of the foliose forms 14°3 per cent., and of the lower 
crustaceous forms as many as 35°6 per cent. But no special 
notice is taken of those species which occur in the regions 
lying between Greenland and the German Alps. A still 
more interesting comparison could be made by comparing 
the Antarctic lichens of America with the Alpine forms of 
the same continent and the Arctic lichens, but as yet the 
material at our immediate disposal makes this impossible. 
These few remarks do favour the view that a very close 
relationship does exist between the Arctic and Antarctic 
lichens, which, however, must date back to the time when 
they were still constituents of one flora. 
It will be seen from this that further collections of 
Antarctic lichens would be of very great interest. 
EXPLANATION OF FIGURES. 
Placodium fruticuloswm, Darbish. 
Fig. 1. An upright podetium showing the small knob-like assimilators, 
which at the top, c, form the roof, which gives this lichen a 
crustaceous appearance. a, substratum ; 6, protothallus ; ¢, 
top of podetium. x8. 
Fig. 2. Longitudinal section of a similar podetium, showing the distri- 
bution of the gonidia, g, in the rounded projecting assimila- 
tors. m, medullary, c, cortical portion, g, gonidia. x 12. 
The PRESIDENT exhibited certain dried plants from 
Yunnan, recently received. They consisted of Gentians and 
Saxifrages, and included several new species. Photographs 
of the sheets of mounted specimens were also shown—a very 
useful addition to the description of new species. 
Mr. Harrow exhibited a series of plants in flower from 
the Garden. 
