47 



genus Larix, the members of which have been lumped under 

 the name L. dahurica. The species I saw so abundantly along 

 the Siberian coast, a few miles from the sea, is L. olgensis 

 A. Henry. Across the" strait in Sakhalin is L. Kurilensis Mayr. 

 I presume it is really the latter which Kudo reports from Yezo as 

 L. dehiirica var kamtschatica . It is actually unknown as a wild 

 plant on Yezo proper, but exists on two islands of the southern 

 Kuriles. 



The actual divergence in species between Yezo and the 

 adjacent mainland is really very remarkable, and must depend 

 very largely on diversity of physical conditions. The Siberian 

 coast is under deep snow all winter and the sea is frozen. In the 

 summer, however, the climate is quite warm, and the vegetation 

 is extremely luxuriant. In the following list of genera, the first 

 figure following the name shows the number of species in Yezo, 

 the second the number of these in the Manchuria, Amur, Ussuri 

 country. Lilum, 6, 3; Iris, 4, 3; Cypripedium, 4, i ; Salix, 18, 7; 

 Qiiercus 4, 2 (I found only Q. Mongolica); Aconitum, 10, i; 

 Aquilegia, 2, i; Acer, 9, 3; Rhododendron, 8, 2; Gentiana, 11, 2. 

 Yezo is very rich in orchids, with 61 species, of which 21 are 

 reported from the mainland opposite. 



A conspicuous feature in the forest about the Kudia River in 

 Siberia is the family Araliaceae, formidably armed plants to be 

 avoided in going through the brush. One I collected proves to 

 be Acanthopanax senticosus (Maxim.) Harms, this and other trees 

 having been kindly identified for me by Mr. Rehder. Yezo has 

 similarly a group of these plants, but with two exceptions, the 

 species are different. Berberis amurensis Rupr., which I collected 

 on the Kudia R., is represented on Yezo by B. regeliana. The 

 Betulaceae are represented on both sides by the same genera, 

 Betula, Carpinus, Corylus and Alnus, but the majority of the 

 species are different. The conspicuous Campanula punctata Lam. 

 is found on both sides, and I observed it as far south as Tsuruga 

 in Honshu. Viburnum sargentii Kochne, which I found on the 

 Kudia R., is lacking in Yezo, which nevertheless has three other 

 species of Viburnum. Tilia amurensis Kom., a handsome tree 

 of the Kudia R., is represented by two other species on Yezo. 

 Such examples could be multiplied over several pages, but 

 enough has been given to show the marked diversity of species 

 in those two lands, separated by no great expanse of sea, and 

 nearly continuous northward. 



