NATURAL AREAS AND REGIONS 



269 



tended in a somewhat irregular line from 

 about longitude 96° \V., near the north- 

 west corner, to about latitude 45° 45' N. 

 on the eastern border. All of the south- 

 western part, and including the Red 

 River vallej' of the North, belongs to the 

 Grassland Formation, all of which was 

 originally treeless except for fringes of 

 forest along certain lake shores and 

 stream borders. Between these two 

 great formations stretched a belt of 

 varying width of deciduous forest which 

 might properly be designated the Decid- 

 uous Forest Formation since it is fairly 

 sharply marked out from the other two. 

 Originally the state had about 31,800 

 sq. mi. of prairie and 52,200 sq. mi. of 

 forest. 



The nature and extent of the five main 

 vegetation areas of Minnesota are deter- 

 mined mainh' by climatic factors. It 

 is probable, however, that the original 

 border line between the forest and the 

 grassland was to some extent determined 

 by prairie fires periodically started by 

 the Sioux Indians, partly to increase the 

 extent of their hunting grounds, and 

 partly to keep back their woods enemies 

 the Ojibwas or Chippewa Indians. 



The five plant formations, deciduous 

 forest, coniferous forest, . oak grove 

 savanna, poplar savanna and grassland 

 or steppe, although in the main well 

 delimited naturally showed considerably 

 overlapping along their borders. Thus 

 in the coniferous forest area numerous 

 outposts of hardwood timber, mostly 

 hard maple, oak and elm occurred and 

 in the southeast irregular tongues of the 

 prairie extend into the deciduous forest 

 formation. Similarly in the southwest 

 and the west hardwood timber formed 

 scattered groves out on the prairie, and 

 followed up along some of the main river 

 valleys like the Minnesota, the Cedar, 

 the Des Moines and the Rock. In each 

 of the five areas the climax stages, of 

 development had probably been reached 

 and each one was characterized by a 

 goodly host of important species. 



1. Coniferous forest. Thus in the 

 coniferous forest area the principal 

 species of trees were white pine (Finns 



slrobus), Norway pine (Pimis resinosa), 

 Jack pine (Pmws hanksiana), white 

 spruce {Picea canadensis), black spruce 

 {Picea mariana), tamarack (Larix lari- 

 cina), balsam fir [Abies balsamea), 

 white cedar {Thyja occidentalis), to- 

 gether with some intermixture of paper 

 birch (Betula papyrifera), aspen (Popuhis 

 tremuloides), red oak {Quercus rubra), 

 bur oak (Quercus macrocarpa), black 

 ash (Fraxinus nigra), green ash (Fraxi- 

 nus lanceolaia), yellow birch (Betula 

 lutea) and mountain agh (Pyrus ameri- 

 cana). The characteristic shrubs are: 

 yew (Taxus canadensis), juniper (Juni- 

 perus communis), willow (Salix dis- 

 .color, S. lucida, S. balsavnfera, S. 

 Candida), beaked hazel (Corylus ro- 

 strata), dwarf birch (Betula pumila var. 

 glandulif era) , hoary alder (Alnus incana), 

 meadow sweet (Spiraea salici folia), 

 red raspberry (Rubus idaeus aculeatis- 

 simus), pin cherry (Primus pennsylva- 

 nica), choke cherry (Prunus virginiana), 

 wild rose (Rosa acicularis), northern 

 gooseberry (Ribes oxyacanthoides) , wild 

 black currant (Ribes floridum), leather- 

 wood (Dirca palustris), mountain maple 

 (Acer spicatum), red osier dogwood 

 (Cornus stolonifera), Labrador tea 

 (Ledum groenlandicum) , leather leaf 

 (Chamaedaphne calyculata), bearberry 

 (Arctostaphylos Uva-ursi), trailing arbu- 

 tus (Epigaearepens), wintergreen (Gaul- 

 theria procumbens), bog rosemary 

 (Andromeda polifolia), blueberry (Vac- 

 cinium pennsylvanicum , V. canadense), 

 cranberry (Vaccinium Oxycoccus, V. 

 macrocarpon) , pipsissewa (Chimaphila 

 umbellata), snowberry (Symplwricarpos 

 racemosus), bush honeysuckle (Diervilla 

 Lonicera), mountain fly honeysuckle 

 (Lonicera caerulea), swamp fly honey- 

 suckle (Lonicera oblongi folia), red 

 berried elder (Sambucus racemosa), 

 downy arrow-wood (Viburnum pubes- 

 cens), highbush cranberry (Viburnum 

 americanum). 



The predominant herbaceous plants of 

 the coniferous forest of the state aside 

 from numerous species of grasses, sedges 

 and rushes, are bracken fern (Pteris 

 aquilina), shield fern (Aspidium spin- 



