EDWARD TTJCKERMAN. 



literature of systematic lichenology. That it is not more widely read 

 and known is probably due to the prevailing fondness for micro- 

 scopic details. It must be confessed, however, that the somewhat 

 involved style in w T hich it was written is in part responsible, for it 

 is a hard book to read. It was addressed to experts, not to begin- 

 ners, and, when it appeared, the older experts were too busy attempt- 

 ing to split up genera and species to an unendurable degree of 

 artificiality, while the younger men, attracted by the writings of 

 Schwendener, Bornet, and Stahl, were too much interested in devel- 

 opmental and physiological questions to care much for systematic 

 works. The Genera Lichenum is a protest against the artificial 

 classifications based almost wholly on the spore characters without 

 regard to other equally important characters, a method first advo- 

 cated by the Italian lichenologists, with De Notaris at their head, and 

 adopted by the Germans and other continental botanists. Tucker- 

 man advocated the systems of Fries modified by his knowledge of 

 exotic forms. His view of species was a large one, and he recog- 

 nized numerous varieties of the type but refused to admit that, if a 

 form differed in any visible respect from the type, it must constitute 

 a distinct species. If his classification is at times less easy to follow 

 than that of the modern continental school, it presents ultimately 

 fewer difficulties and is certainly more natural, and hence more 

 scientific. 



On the completion of his Genera his whole aim was to complete 

 a descriptive work which should include all the species known in 

 the United States. For this work no living botanist had so ripe 

 an experience or such a mass of valuable material as he. Unfor- 

 tunately his health failed, and, being the long acknowledged au- 

 thority on lichens in this country, much of his time was absorbed 

 by correspondents who, at times, ill requited his valuable services. 

 In 1882 there appeared the first volume of his much-desired "Syn- 

 opsis of the North American Lichens," which comprised the Par- 

 meliacei, Cladoniei, and Ccenogoniei. He applied himself industri- 

 ously to the preparation of the second volume, which it was hoped 

 would soon appear ; but death interrupted his task, and it is not 

 now known whether his manuscript is in a state to admit publica- 

 tion.* If not, the loss to American botany will be very great, for 



-Since the above was written it has been learned that the manuscript of 

 the Lecidiacei and Graphidacei was left by Professor Tuckerman in condi- 

 tion for printing, and it is the intention of his family to publish it at an 

 early day. 



