25 GENERAL INTRODUCTION. 



Man)- plants that are quite characteristic of northern latitudes are 

 found in greater or less abundance in isolated localities, such as high 

 mountain sides and cool shaded ravines or deep swamps, far south- 

 ward of their usual homes; and, on the other hand, representatives of 

 many southern species find their way far northward along suitable 

 water-courses, and warm valleys, that penetrate regions clothed in 

 vegetation of a very different type. These seeming peculiarities of 

 distribution are dependent on definite physiographical conditions 

 and are not difficult of explanation, however annoying they may be to 

 those engaged in the determination of distributional areas. Never- 

 theless there are species that are more or less distinctive of certain 

 tolerably well-defined areas, and I present the following as a pro- 

 visional list, fairly characteristic of a Canadian Flora : Ranuficulus 

 flamnmla reptaiis, Coptis trifolia, Di centra Canadensis, Viola rohmdi- 

 folia, V. Canadensis, Arenaria Grceida7idica, Claytonia Caroliniana, Ge- 

 raniwn Robertiamiin , hnpatiens pallida , Oxalis acetvsella, Acerspicatiim, 

 Polygala paticifolia, Poterinm Canadense, Getun macrophylltim, Wald- 

 steinia fragarioides, Potentilla trideidata, Dalabarda repens, Ribes 

 laciistre, Mitella diphylla, M. nnda, Tiarella cordifolia, Epilobiuvi al- 

 pinum, E. palustre lineare, Circea alpina, Aralia trifolia, Cornus 

 Cajiadensis, Lin7i(ea borealis. Aster acurninattcs, Solidago thyrsoidea, 

 S. Virga-aurea alpina, Nabidtis nanus, N. Boottii, Cantpamda 

 rotnndifolia, Vaccinenni idiginosnm, V. ccespitosuni, V. Vitis-Idcea, 

 Chiogenes hispidida, Cassiope hypnoides (Dr. Parry), Cassandra calycu- 

 lata, Kahnia glauca, RJiododendron Ljxpponicum, Rhodora Canaderisis, 

 Ledtuti latifolinm, Pyrola rotnndifolia, Chiinaphila tivibellata, Trien- 

 talis America7ia, Empetriwi nigrum, Bettda glandulosa, Salix Cutleri, 

 Pinns sti'obns, Abies nigra, A. Canadensis, A. balsamea. Thuja occi- 

 dejitalis, Diapensia Lapponica, Orchis spectabilis, Habenaria hyper - 

 borea, H. dilitata. Goody era repens. Lister a cor data, Alicrostylis nwTW- 

 phyllos, Cypripediuni picbesce7is, C spectabile, C. acaule, Trillium gran- 

 dijiorum, T. erectum. T. erythrocarpum, Streptopus roseus, Clintonia 

 borealis, SjHilacena trifolia, S. bifolia. 



