II PREFACE. 



specimens, have enabled me to give a very satisfactory account of our 

 Eiver-weeds. W. H. Beeby, A.L.S., London, England, and Mr. 

 Morong have contributed critical notes on the Spargania of Canada 

 Mr. Beeby having sent my specimens to Norway in order that our 

 northern forms might be compared with Scandinavian types. 



The genus Carex, as was to be expected, gave rise to many perplex- 

 ing questions. Besides availing myself of Prof. L. H. Bailey's mono- 

 graph of the genus, I sent him many specimen s of critical species, 

 and have embodied in the text his remarks and occasionally his 

 descriptions of new species and varieties. While not agreeing with 

 him in every particular, his determinations have generally been ac- 

 cepted as conclusive. Mr. Bennet has rendered invaluable assistance, 

 and besides comparing my specimens with those in his own herbarium 

 has transmitted them to Kew and to Scandinavian specialists for com- 

 parison with the types. From his remarks it is quite evident that the 

 correct nomenclature of our northern carices is not yet settled. 



To the veteran botanist, Dr. Yasey, of the Agricultural Department 

 at Washington, I am deeply indebted. For many years he has 

 examined critical species and confirmed my determinations of the 

 Graminese from all parts of Canada. All the species in this order are 

 named in accordance with his catalogues, and in every case his de- 

 cision has been taken as final. 



In arranging the orders and genera I have followed Bentham & 

 Hooker's Genera Plantarum, and the authority for the genus, as given 

 by them, I have accepted. The preparation of this portion of the 

 Catalogue has entailed much labour, on my part, and though conscious 

 that the results accomplished are far from perfect, I would ask the 

 indulgent criticisms of botanists who can well appreciate the difficul- 

 ties of the work. 



JOHN MACOUN. 



OTTAWA, June, 1888. 



