20 
IOWA ACADEMY OF SCIENCES. 
species. In Cladonia gracilis the squamules are to be 
looked for anywhere on the podetia, while in Cladonia ver- 
ticillata they occur very rarely, and, when present, are 
found only at the bases of the podetia or on the margins 
of the cups. Also in the latter species, the proliferations 
are almost always from the center portions (or cavities) of 
the cups, while in the former they are almost always from 
the margins. Such are the “ear marks,'’ while other dif- 
ferences are less marked, and are difficult to bring out even 
in descriptions. 
In attempting, thus briefly, to give some view of the 
work that is being done on the American Cladonias, we 
have selected for discussion some of the species that have 
been treated more at length, with descriptions, in the 
series of articles by the present author and now appearing 
in the Bryologist. The descriptions can not be repeated 
herein, but may be seen by any who may be interested. 
Besides E. Wainio, another European who has helped 
considerably in the work on American Cladonias, is Mr. 
L. Scriba, of Hochst, Germany. Mr. Scriba aided the pres- 
ent writer several years ago and is now examining speci- 
mens sent him by Mr. G. K. Merrill. 
To the person who wants all rough places made smooth 
and all disagreement and all uncertainty removed, the 
study of Cladonias is an aggravation. But the one who 
will not quail before a task that seems so large and so un- 
certain that he may never hope to complete it, will And in 
the genus a good held for the most discriminating taxo- 
nomic effort. 
Only twenty-four forms of Cladonias have been reported 
from Iowa, while more than sixty are recorded for Minne- 
sota. Our flora is not so rich in these plants, but there is a 
great need of careful collecting, examination of all material 
in the various herbaria of the state, and flnal revision of 
the work. 
Thanks are due to the Bryologist for the cuts from which 
the accompanying flgures are reproduced. 
