PKEFACE. 



This catalogue has been a natural outgrowth of the 

 incorporation of the Middlesex Institute in 1881. The 

 results of numerous excursions in the vicinity of Maiden 

 encouraged wider research, leading to the exploration of 

 the entire county, with publication in view. 



Works known to contain lists of county plants have 

 been carefully examined, among which are Bigelow's 

 " Florula Bostoniensis ;" Hitchcock's " Eeport on the 

 Geology, etc., of Mass. ;" Emerson's " Trees and Shrubs 

 of Mass. ;" a " List of Plants in Maiden and Medford ;" 

 the ' ' Catalogue of the Davenport Herbarium ; "' "A 

 partial list of the native flora of Waltham ; " a " List of 

 introduced plants found in the vicinity of a wool- scouring 

 establishment" in North Chelmsford, by Rev. W. P. 

 Alcott ; and miscellaneous papers in the " Proceedings of 

 the Boston Society of Natural History," Hovey's Magazine, 

 and other publications. 



The verification of these lists has been no light task. 

 Where no specimen exists, where it has been impossible 

 to find the original authority upon which a plant outside 

 its recognized limits has been reported, or where there is 

 a strong probability of wrong determination, the authors 

 have excluded such names from the catalogue, thinking it 

 better to lose several species which may be in the county 

 than admit one which would be justly open to criticism. 

 Various public and private collections have been examined 

 for rare species ; while holidays and vacations have been 

 for six years largely devoted to botanical expeditions 

 which have embraced within their scope, though very 

 imperfectly, every section of Middlesex. 



