"360 Part IV. Chapter 2. 
Viola glabella Nutt. Arnica latifolia Bonz. 
Geranium erianthum DC. Ledum latifolium Ait. 
Lupinus nootkatensis Don. >» palustre L. 
Astragalus alpinus L. Pirola uniflora L. 
Oxytropis Lambertii var. sericea Nutt. » rotundifolia L. 
Hedysarum Mackenzii Rich. Trientalis arctica Fisch. 
Potentilla nana Willd. Mertensia paniculata Don. 
Poterium(Sanguisorba) d Gray Pedicularis sudetica Willd. 
Rosa nutkana Presl. Boschniakia glabra C. A. Mey. 
Sedum Rhodiola DC. Pinguicula villosa L. 
Cornus suecica L. Rumex occidentalis Wats. 
Viburnum pauciflorum Pyl. Streptopus amplexicaulis DC. 
Chapter I. North American Temperate Zone: Atlantic Section. 
The temperate zone is meant to include that part of the continent which 
does not have a decidediy rigorous climate, and which does not have a suffi- 
cient amount of heat to be considered as of torrid climate. The word is here 
used in its physical zone sense, because it affords a convenient means of classi- 
fying the phytogeographic sections and regions of our country in a broad 
and general manner. Approximately the temperate zone of North America 
may be considered to lie between the isothermal lines of 40° and 70° Fahren- 
heit (4,4°—21,1° C) the latter representing the boundary of the physical torrid 
zone. Three sections of this zone are recognizable: the Atlantic, the Pacific 
and the Mexican. 
Atlantic Section. The Atlantic Section (or Province) of the North American 
Temperate Zone comprises in the main the territory of North America which 
is drained into the Atlantic Ocean. Three subdivisions are to be noted, viz., 
the coastal, the mountainous and the plain. The treatment of the several 
phytogeographic regions of the coastal portion of the Atlantic Section will 
now be considered categorically. It must be understood that the regions, district, 
areas, formations form the natural phytogeographic entities, while the classi- 
fication into zones, sections etc. has been purely arbitrary to assist in demar- 
cating the geographic location of the regions now briefly to be considered. 
1. St. Lawrence — Great Lake Region. 
As the name indicates this region occupies the valley of the St. Lawrence 
River and the basin of the Great lakes for some distance on either side of 
these natural waterways. In the main, the flora is a homogeneous one with 
the White pine Pinus strobus, P. resinosa, Acer saccharum (= A. saccharinum), 
Acer pennsylvanicum, Sorbus americana, Betula lenta and B. Iutea as prominent 
