656 DR JAMES STARK ON THE SHEDDING OF 
leaves on its branches during summer, but only one year’s growth during the 
winter. 
Pinus excelsa (Bhotan Pine), in my locality shows the same peculiarity: 
retaining on its branches during winter the leaves of that year’s growth, and 
throwing off the leaves of the previous year during October. 
Pinus sylvestris (Scotch Fir).—This species, unlike the preceding, retains on 
its branches during the winter the leaf-fascicles of two years’ growth. During 
the whole summer, therefore, it presents three years’ growth of leaves; but 
towards the end of September or beginning of October, according to the season, 
the third previous year’s growth of leaves assumes a yellow colour and drops off, 
leaving only two years’ growth of leaves to withstand the colds of winter. All 
the varieties of P. sylvestris show this peculiarity; and trees raised from seeds 
brought from the Black Forest of Germany, from Russia, Holland, Switzerland, 
and the Highlands of Scotland, alike retain on their branches, during the winter, 
two years’ growth of leaf-fascicles. 
Pinus Laricio (Corsican Pine).—This resembles the Scotch Fir in retaining 
during winter two years’ growth of leaves, and shedding in October the leaves 
of the third previous season’s growth. 
Pinus Cembra (Swiss Stone Pine).—In general, this species retains on its 
branches, during the winter, the leaf-fascicles of three years’ growth, throwing 
off in October those of the fourth previons season’s growth. In my high locality, 
nearly a half of the trees retain during the winter only two years’ growth of 
leaves; but, as yet, I have failed to trace the cause of this. 
Pinus Austriaca (Austrian Pine).—This differs from all the preceding in 
that it retains on its branches, during the winter, four seasons’ growth 
of leaves; throwing off in October the leaves_of the fifth previous season’s 
growth. As the whole plant is robust, the branches heavy aud spreading, 
and the leaves long and coarse, this tree, from retaining so many years’ 
growth of leaves, gives a greater amount of shelter than any other of the 
genus: and in a landscape it is, in spring, one of the most beautiful of the 
pines, as its very large white silky shoots offer such a fine contrast to its dark 
heavy foliage. 
Pinus pumilio, P. uncinata, and P. Mugho, agree with the Austrian pine, in 
retaining during winter the leaves of four seasons; throwing off, early in 
October, the leaves of the fifth previous season’s growth. 
In order to show how valuable this character of defoliation (or, rather, 
cladoptosis) is in enabling us to ascertain the analogies of the species of Pinus, 
may be mentioned the disputed point as to whether P. pumilio and the allied 
forms P. wacinata and P. Mugho are merely varieties of Pinus sylvestris, or are 
wholly distinct. Loudon, in his “Encylopedia of Trees and Shrubs,” has 
written of these trees—“ They bear such obvious marks of belonging to the 

