CONTENTS. 



Page. 



Introduction, Itinerary and Acknowledgments, by Alexander G. Ruthven 13 



Description of the En\1ronmental Conditions and Discussion of the Geographic Rela- 

 tions of the Biota, by Alexander G. Rutliven 17 



Location and Description of the Sand Region 17 



Topograpliy 17 



General Soil Conditions 20 



Habitats ■ • 20 



Sand Ridges 21 



Beach of Saginaw Bay 21 



Wooded Swamps 22 



Mesophytic Woods . 23 



Sedge and Grass Swamps 23 



Transient Ponds 23 



Permanent Ponds 24 



Streams 25 



Saginaw Bay 26 



The Geographic Relations of the Terrestrial Flora and A'ertebrate Fauna of the Sand 



Region 27 



Climate 28 



Precipitation 28 



Temperature 28 



Local and General Distribution of the Biota 30 



Literature 31 



Ecological Relations of the Flora, by G. H. Coons 35 



Physiographic Conditions 36 



Ecological Relations 37 



Hydrophytes — Fresh Water Formations 37 



Helophytes — Swamp Formations 38 



Ampliibious Formations — Carex, Juncus and Scirpus Association.s 38 



Reed — Swamp Formation — Pliragmites Association 40 



Bush Swamp Formation — Alnus Association 42 



Wooded Swamp Formation — Birch- Willow Association 43 



Mesophytes — Forest Formation — Poplar- Bircli-Maple Association 44 



Psammophytes — Beach Formations 45 



Dune Formation — Calamo\ilfa — Ammophila Association 46 



Dune Heath Formation 48 



Dune Bushland Formation 49 



Dune Forest Formation — Jack Pine Association 49 



Summary of Ecological Relations 54 



Fungus Formations 65 



Phytogeographical Relations 58 



General Summary 60 



Literature Cited 61 



Catalog of Plants, by C. K. Dodge 65 



Introduction and General Description of tlie Region 65 



Plants of tlie Beaches 68 



Plants of the Dunes 70 



Geograpiiic Notes 71 



Acknowledgments 71 



List of Species 72 



