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In 1814, Dr. Jacob Bigelow published his Florula 

 Bostoniensis, which embraced in its plan a considerable 

 portion of Middlesex. This work, which passed through 

 a second edition in 1824, and a third in 1840, became at 

 once a standard authority, and gave a mighty impulse to 

 the study of botany. 



For more than a quarter of a century, B. D. Greene, a 

 keen and accurate observer, whose ample fortune happily 

 left him at liberty to pursue his favorite study, herborized 

 extensively in Tewksl)ury and adjacent towns. He was 

 also an unconscious contributor to the Desmid flora of the 

 county. On specimens of Utricularia collected by him at 

 Tewksbury and transmitted to Swedish herbaria, Lager- 

 heim has detected seven new species and fourteen new 

 varieties of Desmids which are enumerated in their place 

 among the AlgtB. 



Prof. Edward Tuckerman, while residing in Boston or 

 vicinity, contributed largely to our knowledge of the 

 county flora, more especially of the Lichens, of which he 

 made an extensive collection. 



Eev. J. L. Russell, a diligent student of Cryptogamic 

 botany, while settled at Chelmsford, made collections of 

 Musci, Hepaticfe and Lichens, publishing from time to time 

 the result of his researches. 



George B. Emerson, 1840-1845, repeatedly traversed 

 Middlesex, as indeed every other county of the state, in 

 search of material for his "Report on the Trees and 

 Shrubs growing naturally in the Forests of Massachusetts," 

 which appeared in 1846, and has been used ever since as 

 the best available text-book for the study of our trees. 



Charles E. Perkins, whose early death in 1883 cut short 

 ^ botanical career of much promise, had been at work for 

 several years gathering data for a Flora of Boston and 



