Lichens of Minnesota. 249 



LICHENS OF MINNESOTA. * 

 By Albert C. Herre. 



The thanks of botanists in general and of students of Hchens 

 in particular are due to Professor Fink for the care and discrimi- 

 nation he has shown in preparing this volume, the best piece of 

 work yet published on lichens in this country. 



The first thirty-six pages are taken up by the introduction 

 in which the aims of the work are considered and a careful r^sumd 

 is given of the structure, functions, and life relationships of li- 

 chens. This part is a very clear and able presentation of the 

 essential facts concerning lichens and should be read by every 

 one who dtsires a general idea of these plants. After setting 

 forth the leading opinions on the subject, Professor Fink de- 

 cided for practical reasons and because of the lack of agreement 

 among botanists that it was best in the present paper to follow 

 Engler and Prantl in recognizing the class Lichenes, instead. of 

 distributing lichens among the fungi. But he further states that 

 in a general systematic treatment further study may lead to the 

 distribution of lichens among the fungi, to the exclusion of the 

 class Lichenes. The reviewer, who believes that Lichenes must 

 eventually be discarded as a class, hopes that Professor Fink 

 rnay soon be able to publish his views upon this point in some 

 detail. 



The author states (p. 33) "But it is certain that the fungus 

 forming the lichen takes more or less of crude or elaborated food 

 materials from the substratum," but it might have been better 

 had he given some illustrations or data on this topic. For it is 

 likewise certain that in at least some cases the lichen derives 

 no hing from the substratum; as an instance I may cite the li- 

 chens growing on the iron fence which until recently surrounded 

 the grounds of the Normal school in San Jose, Cal. 



The reviewer agrees with Professor Fink (p. 36), that "it 

 is probably not worth while to take time to remove lichens from 

 any trees of temperate regions for the sake of saving the trees 

 from injury," but it has been found best in some of our California 

 fruit districts to remove the lichens from the fruit trees because 

 of the injurious insects which they harbor. 



Following the introduction is the descriptive catalog of 

 211 pages, which includes an outline of classification, an artificial 



*A Review of "The Lichens of Minnesota," by Bruce Fink. Contributions from the 

 United States National Herbarium, volume 14, part I. pp viii-269-XVII, with a frontis- 

 piece 51 plates and 18 text figrures; bsued June 1, 1910. 



