26 
GENERAL INTRODUCTION. 
Many 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 : Ranunculus 
flammula replans, Coptis trifolia , Dicentra Canadensis , Viola rotundi- 
folia , V. Canadensis , Arenaria Groenlandica , Claytonia Caroliniana , Ge- 
ranium Robertianum, Imp atiens pallida , Opcalis acetosella , Acer spicatum , 
Polygala paucifolia , Poterium Canadense , Geum macrophyllum , Wald- 
steinia fragarioides , Potentilla tridentata , Dalabarda repens , Ribes 
lacustre, Mitella diphylla , M. nuda , Tiarella cor difolia, Epilobium al- 
p inum , E. palustre linear e , Circea alpina , Aralia trifolia , Cornus 
Canadensis , Linncea borealis , Aster acumiuatus, Solidago thyrsoidea , 
.S'. Virga-aurea alpina , Nabulus nanus , TV! Boottii , Campanula 
rot undifolia , Vaccineum uliginosum , K ccespitosum , /d Vitis-Idcea, 
Chiogenes hispidula, Cassiope hypnoides (Dr. Parry), Cassandra calycu- 
lata , Kalmia glanca, Rhododendron Lapponicum , Rhodora Canadensis , 
Ledum latifolium , Pyrola rotundifolia , Chimaphila umbellata , Trien- 
talis Americana , Empetrum nigrum , Betula glandulosa, Salix Cutler i, 
Pinus strobus, Abies nigra , M. Canadensis , M. balsamea, Thuja occi- 
deutalis, Diapensia Lapponica , Orchis spectabilis , Habenaria hyper- 
borea , H. dilitata , Goodyera repens , Listera cor data, Microstylis mono- 
phyllos , Cypripedium pubescens, C. spectabile, C. acaule , Trillium gran- 
diflorum , 71 erectum, T. erythrocarpum , Streptopus roseus , Clintonia 
borealis, Smilacena trifolia, S. bifolia. 
