its innumerable and beautiful forms. The words of the 
Psalmist : ‘‘ Coeli enarrant gloriam Dei, et opera ma- 
nuum egus annunciat firmamentum” are in an equal 
measure applicable to 27ora’s realm. 
This little volume is designed as an aid in a prelimin- 
ary determination of a limited number of plants, indigi- 
nous to Maryland and Virginia. The works cited in 
connection with the species are the most recent accessible 
books on our flora; these should be consulted in critical 
determinations, as should also the various botanical jour- 
nals, published in the Eastern United States. A compre- 
hensive bibliography has been given by W. R. Maxon 
in his ‘* List of the Ferns and Fern Allies of North 
America North of Mexico with Principal Synonyms 
and Distribution.” [Proc. U. S. Nat. Mus. 23: 619- 
651. 1901. ] 
With the exception of a few species, these notes are 
primarily the result of field-studies, more or less inter- 
rupted since 18y6. The material in the U.S. National 
Herbarium has been consulted in order to include all 
known localities for some of the rarer species. 
I am indebted to AZr. F. J. Tyler for the illustrations 
and indirectly to all my co-workers, whose names ap- 
pearin connection with some of the species. 
Washington, D. C. Lvar Tidestrom . 
