GENERA AND SPECIES. 159 



ommended for the cure of jaundice (according to the 

 similia similihus curantur principle of homeopaths). 



4. Cetraria lacunosa. Thallus foliose, rather large, 

 upper surface reticulate, bluish-green tinged with 

 gray ; lower surface brownish. Apothecia medium. 

 Disk chestnut-brown, base sometimes perforate, as in 

 Parmelia perforata. Spores typical, 7.5;u, X 5./);tx. 



Tiiis species is often confounded with C. ciliaris. 



5. Cetraria cucullata. Thallus fruticose, terminal 

 lobes rather finely divided ; straw color, darker toward 

 base. Apothecia large, attached to che lower surface 

 of turned terminal lobes. Disk chestnut-brown. Spores 

 typical, 9.5/x X 5.5/x. 



6. Cetraria Islandica. Thallus fruticose, lobes 

 comparatively narrow, rolled, rigid, erect; margin 

 lined with rigid cilia ; upper surface chestnut-brown, 

 lower surface somewhat lighter. Apothecia medium. 

 Disk chestnut-brown. Spores typical. 



This lichen, commonly known as " Iceland moss," 

 has enjoyed great popularity as a medicinal substance 

 and as an article of diet. It is still extensively used as 

 food for convalescents and those having weak stomachs. 

 Icelanders powder it and use it as flour. In Scandi- 

 navia it is used as fodder for cattle. It yields a 

 brown color which was once much used for dyeing 

 woollen goods. 



According to the United States Dispensatory, Ice- 

 land moss is demulcent, nutritious and tonic, well cal- 

 culated for affections of the mucous membranes of the 

 lungs and bowels in which the local disease is asso- 

 ciated with debility of the digestive organs, or the 



