PREFACE. 



In June, 1887, the Lackawanna Institute of Scranton published a 

 "preliminary list" of the plants in the Lackawanna and Wyoming Val- 

 leys. The author, Prof. W. R. Dudley, then of Cornell University, 

 brought together the results of his own collecting, and that of several local 

 collectors, also Prof. Thomas C. Porter's discoveries on the adjacent moun- 

 tains. This list, together with the interest aroused by the Institute 

 during its summer school in 1889, under Prof. Dudley, made the present, 

 far from complete, flora possible. 



The territory included is the same as that of the preceding list, namely, 

 the Lackawanna and Wyoming Valleys and the mountain ranges enclos- 

 ing them. Localities are occasionally mentioned near to but outside these 

 limits to stimulate our botanists, who may have access to them, to a more 

 diligent search. 



The catalogue has been prepared from the carefully kept notes of 

 Prof. Dudley, made from his personal observations in 1889, 1890, and 

 the autumn of 1891, combined with the results embodied in the printed 

 list of 1887 ; from notes kindly sent him by Prof. T. C. Porter, of Lafay- 

 ette College, the best authority on the plants of Pennsylvania ; and from 

 reports made to him by the different botanists in the valleys. Credit 

 has been given each in the text, the single word "Davis" referring to 

 Mr. R..N. Davis, of Archbald; "Graves," to Mr. W. R. Graves, of 

 Scranton; "Miss Carlson" to Miss Eleanor Carlson, of West Pittston. 



Plants quoted as "common," "abundant," or "frequent," are so quoted 

 on the authority of these botanists, each in his own locality, aided by 

 the general observations of Prof. Dudley. 



The classification and nomenclature corresponds, in the main, to that 

 of the sixth edition of Gray's Manual, to which students are directed 

 for a full description of all plants growing without cultivation. 



The few cultivated plants, noticed for the benefit of my classes, will 

 be found described in Gray's Field, Forest and Garden Botany. 



Although crowded with the work of his department at Cornell Uni- 

 versity, Prof. Dudley has taken the time to rewrite the families Cistacca, 

 Ericaceae, Cupuliferce, Salicacea, Juncacea, Cyperacea and Graminea:. 



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