144 ARTHUR G. VESTAL. 



determined by local conditions of moisture; these are usually 

 not characteristic of any one vegetation province; and ruderal 

 associations, composed of introduced plants. Plant names used 

 are those of Gray's Manual, seventh edition. 



Associations of the Northeastern Conifer Province. 



The culminating type of vegetation in the Northeastern 

 Province is the balsam-spruce-birch forest, which is developed 

 successively through lichen, heath, and different pine stages, 

 in xerophytic situations; and through bog and bog-forest stages 

 in water and wet ground. Only those associations are listed 

 which are represented by distinct areas in the region studied. 



Cham cedaphne Association (Gates, '13: 57). No grasshoppers 

 were taken in the open bogs of cassandra. In Ontonagon county, 

 northern Michigan, thickets of cassandra, alder, wax myrtle, 

 high-bush cranberry, etc., are the habitat for Podisma glacialis 

 .and Melanoplus islandicus (Morse, '06: 70). 



Thuja Association (Gates, '13: 66).- The cedar or arbor- 

 vitae growth known as Rees's bog, near the shore of Burt Lake, 

 south of Douglas Lake, was studied. In this bog the peat soil 

 is less than two feet deep, the substratum being sand or gravel. 

 It is drained through the porous soil into Burt Lake. No bare 

 soil is exposed, but partly moss-grown logs lying upon the surface 

 are not infrequent. Trees are usually not more than twenty feet 

 in height, but are close together, and cast a deep shade. Thuja 

 occidentalis is the dominant species; Larix laricina, tamarack, 

 and Picea mariana, black spruce, occur sparingly. The surface 

 is a thick carpet of Sphagnum; many peat-bog plants, as Cornus 

 canadensis, orchids, ericads, etc., are present, more abundantly 

 in less shaded parts. The only grasshopper species taken in 

 this bog. is Melanoplus islandicus. 



Aspen Association (Gates, '13: 77). The extensive sandy 

 pine lands of the region are now r , as a result of fires and cutting, 

 practically all occupied by the aspen forest. The dominant tree 

 is the large-toothed aspen, Populus grandidentata. Other fre- 

 quent species are paper birch, beech, red oak, hard maple, red 

 maple, w r ild cherry, Primus pennsylvanica, white pine, pitch pine. 

 The undergrowth, quite similar to that of the pine forest, is 

 chiefly composed of bushy blueberry plants, Vaccinium penn- 



