368 BOTANICAL GAZETTE [May 
which there is a dominance of low evergreen shrubs. Warming 
and Graebner use the term heath much more comprehensively, 
speaking of moss and lichen heaths and coniferous heaths. 
Along Lake Michigan the heath formation becomes more and 
more prominent northward. A well-marked juniper or bear- 
berry heath is rare at the south end of the lake, while extensive 
Te 
—————— eames een eine Nem cP ce 3 
? : A ; ter. 
1G. 21.—Rejuvenated dune on Beaver island. Wind-sweep at the cente 
Coniferous forests on each side that are not yet destroyed. 
areas are covered by the heath on Beaver and North Maniton 
islands and on the neighboring mainland. us 
During the development of a heath, the vegetation partakes 
of the nature of the formation which preceded it, whether dune 
or beach cr terrace. Before the true heath plants cover = 
soil, the open places are inhabited more or less abundantly : 
such plants as Prunus pumila, Salix glaucophylla and adenophy! é 
Solidago humilis Gillmant and nemoralis, Aster laevis, Calamagrosis 
longifolia, Smilacina stellata, Lithospermum Jurtum, Artemisia se 
densis, Rhus Ti oxicodendron, Rosa Engelmanni. On fossil beache 
