NATIONAL ACADEMY OF SCIENCES. 



it is certain that he had in his possession a large amount of new 

 material, and no one could so well as he treat the difficult groups 

 Lecidiacei and Verrucariacei. 



A word should be said about Professor Tuckerman's views with 

 regard to the Schwendener theory. Following the earlier indica- 

 tions of De Bary, Schwendener, by a minute study of the thallus 

 of lichens, brought forward proofs to show that the gonidia of 

 lichens had no real genetic connection with the hyphse, but were, in 

 fact, algae upon which the hyphse were parasitic ; in other words, 

 what is called a lichen is, properly speaking, a fungus of the order 

 Ascomycetes, which is parasitic on some alga ; in most cases a species 

 belonging either to the Palmellacece or the Nostocacece. The botan- 

 ical world was divided in opinion, and, for the last fifteen years, the 

 so-called algo-fungal theory of licheus has given rise to endless con- 

 troversies of a personal and very acrimonious character. As a rule, 

 the systematic lichenologists were opposed to the theory, while the 

 histologists supported it. Professor Tuckerman, who began his 

 studies at a time when microscopic technique had not reached its 

 present perfection, could hardly have been expected to take a very 

 active part in a direction requiring difficult microscopical work. It 

 is said that at first he was inclined to favor the theory, but if so, he 

 soon changed his views and sided with the opponents of the theory. 

 It must be said to his credit that his references to the subject were 

 always courteous and dignified in marked contrast with the course 

 of some other well-known lichenologists. The most definite expres- 

 sion of his opinion in print is to be found in the American Journal 

 of Science and Arts of February, 1879, where, under the title of 

 " The Question of the Gonidia of Lichens," he reviewed the first 

 part of Minks' "Beitraege zur Kenntnissdes Baues und Lebens der 

 Flechten " Minks had observed small green bodies in the hyphse, 

 which finally escaped from them and developed into gonidia. In 

 his review Tuckerman confirms the statement of Minks with regard 

 to the existence of the green bodies called by Minks microgonidia, 

 and remarks that he has observed them himself in Parmelia tiliacea 

 v. flavicans of Cuba, but he does not go so far as to say that he saw 

 them develop into gonidia. He accepts Minks' statements on this 

 point, however. 



The life of our lamented associate was one devoid of some of the 

 incidents which make the lives of many men of science picturesque. 

 It is a simple story, not of struggles against poverty and the enmi- 



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