The work of the "Danmark-Expedition" has brought to a pre- 

 Hniinary close the purely floristic side of lichen collecting in 

 Greenland, as practically the whole coast of the land has now been 

 investigated. Later collections will assuredly be able to find one 

 thing or another new, but we already have a view over the floristic 

 character of the lichen vegetation, thanks to the persevering scientists 

 who in the course of time have added to the collections in the Bo- 

 tanical Museum of Copenhagen. 



What has been known hitherto of the Greenland lichens is to 

 be found mainly in the papers by Deichmann Branth and Grøn- 

 lund in the "Meddelelser om Grønland", Hefte III (1888j and the 

 Appendix (ibidem 1892), as also in later papers by Branth and by 

 Wainio (ibidem Hefte XVIII and XXX). 



Our floristic knowledge now extends so far, that it will undoubt- 

 edly be of greatest interest to begin a biological and ecological 

 investigation of these plants, not only for the arctic species but also 

 for the species of the whole world. Far loo little attention has 

 hitherto been paid to the part played by the lichens in the existing 

 plant-associations and to the mutual relations between the lichens 

 and the widely different natural conditions offered them at their 

 varied and different places of growth. 



The species mentioned here have almost all been found in 

 Greenland before. A single species is however remarkable, as it 

 has hitherto not been found in that country, or at least is not pre- 

 sent in the collections of our Museum, namely Diifourea miiricaia, 

 which was found for the first time in arctic regions by Тн. Fries 

 in Spitzbergen. 



A discussion of the correctness of the more difficult species has 

 been omitted, as it would lead as too far here — even though the 

 subject might in itself be tempting for several Parmelia species and 

 a few others. 



Under each species reference is made to a main work, where 

 further information on the literature can be obtained. 



15* 



