152 



of the species. But the clearly differing forms, papulosa, stipata 

 and molariformis, named by European authors, and adopted by 

 Robbins and Blake and Evans, found wherever the species 

 occurs, are so useful in separating them, that such differentia- 

 tions seem a necessity. Or, another example, Cladonia cristatella. 

 This work gives the species, and only two varieties, paludicola, 

 which was long ago separated from C. cristatella, by European 

 authors, and is now reduced to synonymy, for C. incrassata; 

 and densissima, which is based apparently on one specimen 

 found on a fence post near Oxford, Ohio, which seems near 

 Robbins f. squamosissima. Yet Evans, in his Cladoniae of Con- 

 necticut (1930) found ten forms of C. cristatella, named by 

 Tuckerman, Vainio, Robbins, and Merrill, some of them sixty 

 years ago, which seem valid and essential in any complete 

 treatment of the genus in America. 



Incomplete study seems to have been given to the KOH re- 

 actions on species of Cladoniae. In the key, several species are 

 mentioned as "KOH plus," but the color reaction is not stated. 

 In C. subcariosa, no mention is made of any reaction, although 

 the prompt yellow, then red reaction on this species is its most 

 helpful determinant, among other species somewhat resembling 

 it. KOH reactions are not mentioned for C. rangiferina, tenuis, 

 alpestris, floridana, santensis and cariosa, though all have been 

 recorded, for some years, by other American and European 

 students. Such lack of completeness lessens the value of this 

 book and makes it necessary for us to continue to use other 

 works; Evans, Robbins and Blake, Annie Lorain Smith and 

 Lindau, for such chemical reactions. 



The treatment of foliose and crustose lichens, seems to be 

 very helpful. Some of the illustrations are taken from the "Li- 

 chens of Minnesota," and a few are new, but there should be more 

 of them. Some of the fine photographs by Prof. Fink in issues of 

 the Bryologist, in the years 1905-1910, would merit inclusion in 

 such a work as this. 



This book will be helpful to lichen students and will increase 

 interest in the subject. But, from comparison with other work 

 in this field, especially the European authors, and American 

 workers on particular genera, it seems just to say that the author- 

 itative Manual of American Lichens has yet to be issued. 



Raymond H. Torrey 



