MAKYI.ANI) WEATHER SERVICE 



"flora of Maryland" is to speak of its plants considered from the 

 systematic view-point as members of families, genera and species; to 

 speak of the "vegetation of Maryland" is to allude to its plants from 

 the physiological view-point as being trees, shrubs or herbs, as being 

 aquatic, palustrine or terrestrial, as independent, saprophytic or 

 parasitic, as hygrophilous, xerophilous or succulent, and the like. 



There has not yet been made a complete enumeration of the plants 

 of Maryland, and we cannot therefore enter on a detailed considera- 

 tion of the Floristic Plant Geography of the state. As much as may 

 be said with the material now on hand forms the subject matter of 

 Part II. of this volume. The flora of Maryland is that of the Middle 

 Atlantic states, — the greater number of its species range beyond its 

 borders northward to Xew England and the Maritime Provinces, 

 westward to Michigan and Missouri, or southward to the Carolinas 

 and Georgia. The mountainous western part of the state has many 

 species ranging northward, the coastal counties are rich in species 

 ranging southward. This results in a marked difference in the flora 

 of the mountain, midland and coastal parts of the state. Differences 

 of flora are known to have their basis partly in the past history of 

 plant distribution and migration, and partly in the present climatic 

 conditions, of which temperature and rainfall are the chief. In 

 Maryland the temperature differences between the Mountain and 

 .Midland Zones may be held accountable for their floristic diffei-enees, 

 hut between the Midland and Coastal Zones other factors take pre- 

 cedence in causing the distinctness, a matter which will be discussed 

 in Part II. 



The principal subject matter of this volume is the Ecological Plant 

 Geography of Maryland, which is here treated in its general descrip- 

 tive phases. Maryland lies in the midst of a region in which the 

 dominant vegetation is the deciduous forest, a type of plant life found 

 to characterise all regions in which there is an abundant rainfall 

 well distributed through the growing season, together with a cold or 

 dry season lasting for a few months. Before settlement by Euro- 

 peans the present area of Maryland was undoubtedly covered by con- 

 tinuous forest. Only here and there were there restricted areas of 

 marsh, hog or bare rock, in which local conditions hostile to tree 



