INTRODUCTION. 3 



trees which do not also occur in Sagkalin or in the northern Japanese islands. In the four 

 islands of Yezo,' Hondo, Shikoku, and Kyushu, therefore, we now find 220 trees divided 

 among ninety-nine genera, or only five less than occur in the immense territory which 

 extends from Labrador to the Rio Grande and from the shores of the Atlantic to the eastern 

 base of the Rocky Mountains. Neither Cycas revoluta nor Trachycarpus (Chamaerops) excelsa 

 is included in the Japanese list, as the best observers appear to agree in thinking that these 

 two familiar plants are not indigenous to Japan proper. I have omitted, moreover, a few 

 doubtful species from the Japan enumeration, like Fagus Japonica, Maxim owicz, and Abies 

 umbellata, Mayr, of which I could learn nothing in Japan, so that it is more probable that 

 the number of Japanese trees will be increased than that any addition will be made to the 

 silva of eastern America. 



The proportion of trees to the whole flora of Japan is remarkable, being about 1 to 10. 14, 

 the number of indigenous flowering plants and vascicular cryptogams being not very far 

 from 2,500 species. Still more remarkable is the large proportion of woody plants to the 

 whole flora. In Japan proper there are certainly not less than 325 species of shrubs, or 550 

 woody plants in all, or one woody plant in every 4.55 of the whole flora, a much larger 

 percentage than occurs in any part of North America. 



The aggregation of arborescent species in Japan is, however, the most striking feature in 

 the silva of that country. This is most noticeable in Yezo, where probably more species of 

 trees are growing naturally in a small area than in any other one place outside the tropics, 

 with the exception of the lower basin of the Ohio River, where, on a few acres in southern 

 Indiana, Professor Robert Ridgway has counted no less than seventy-five arborescent species 

 in thirty-six genera. 1 Near Sapporo, the capital of the island, in ascending a hill which rises 

 only 500 feet above the level of the ocean, I noticed the following trees : Magnolia hypoleuca, 

 Magnolia Kobus, Cercidiphyllum Japonicum, Tilia cordata, Tilia Miqueliana, Phellodendron 

 Amurense, Picrasma ailanthoides, Evonymus Europams, var. Hamiltonianus, Acer pictum, 

 Acer Japonicum, Acer pahnatum, Rhus semialata, Rims trichocarpa, Maackia Amurensis, 

 Primus Pseudo-Cerasus, Primus Ssiori, Pyrus aucuparia, Pyrus Toringo, Pyrus Miyabei, 

 Hydrangea paniculata, Aralia spinosa, var. canescens, Acanthopanax ricinifolium, Acanthopa- 

 nax sciadophylloides, Cornus macrophylla, Syringa Japonica, Fraxinus Mandshurica, Fraxinus 

 longicuspis, Clerodendron trichotomum, Ulmus campestris, Ulmus scabra, var. laciniata, 

 Morus alba, Juglans Sieboldiana, Betula alba, Betula alba, var. Tauschii, Betula alba, var. 

 verrucosa, Betula Erinani, Betula Maximowicziana, Alnus incana, Carpinus cordata, Ostrya 

 Japolica, Quercus crispula, Quercus gosseserrata, Castanea vulgaris, Populus tremula, Picea 

 Ajanensis, Abies Sachalinensis, forty-six species and varieties. Within five miles of this hill 

 also grow Acer spicatum, var. Kurunduense, Acer Tataricum, var. Ginnala, Styrax Obassia, 

 Aphananthe aspera, Quercus dentata, Quercus glandulifera, Alnus Japonica, Salix subfragilis, 

 Salix Caprea, Salix stipularis, Salix acutifolia, Salix viminalis, and Populus suaveolans, in all 

 sixty-two species and varieties, or more than a quarter of all the trees of the empire, which are 

 crowded into an area a few miles square, in the latitude of northern New England, in which, 

 north of Cape Cod, there are only about the same number of trees. 



1 See Proc. U. S. Nat. Mug. 1882, 52. Garden and Forest, vi. 148. 



