74 



The accompanying introductory note by Dr. Howe, curator of 

 the Thoreau Museum of Natural History at Concord, Mass., 

 fully explains the basis upon which the classification followed 

 here is made. The writer wishes to here make public acknowl- 

 edgment of the tireless work of Dr. Howe in completely trans- 

 posing this entire list from the one system to the other, under 

 most unfavorable circumstances. Thanks are also due him for 

 reading of the proofs of this article. 



Using Dr. Howe's transposed list, the writer thought it best 

 to use Tuckerman's nomenclature of families and genera, in so 

 far as they fitted into the new scheme as a basis of procedure. 

 So far as possible this has been done, the equivalent genus and 

 species being placed under the old name following an equality 

 ( = ) sign. In some cases the Tuckerman genus name has been 

 dropped entirely in the new scheme. In this case, since there is 

 at present no Tuckerman equivalent, the new nomenclature is 

 placed first, with the old equivalent of Tuckerman following- 

 An asterisk (*) before a genus shows where this plan has been 

 followed. Certain new genera indicated in the equivalents have 

 also been inserted in the scheme in their proper and relative 

 places to give a general idea of the new nomenclature as far as 

 represented in this list, and as a sort of cross reference. Such 

 genera are indicated by reference to the old Tuckerman genus, 

 i. e., Biatorella (see Lecanora) . 



Foreword 



Not since the year 1823 has a single attempt been made to 

 catalogue the lichens growing in the vicinity of New York City. 

 It was in that year that Halsey, supplementary to the list 

 prepared by Torrey in the year 1819, succeeded in compiling a 

 list of some 180 species found or reported to be found within 

 a radius of 30 miles of City Hall, New York City. 



Whether it is on account of their lowness in the plant kingdom, 

 or of the difficulties attending their study, it is apparent that a 

 field, wide and rich in innumerable forms, and entirely free from 

 competitors, is open and waiting for one who desires to enlarge 

 and enrich the already existing, but meager and scattered data 

 concerning the lichen flora of this region. 



