115 



strong solutions of potassium hydroxide (KOH) or calcium 

 hypochlorite to the squamules or podetia. It works best on the 

 back of primary squamules. A prompt and often striking color 

 reaction is obtained, through the effects of these alkalis upon 

 the acids in the lichen thallus. The solutions may be obtained 

 from a druggist or the chemicals may be purchased and solu- 

 tions made at home; an old iodine dropper bottle is a good con- 

 tainer. In some cases where other characters may not be posi- 

 tive, a species may be accurately determined by the yellow, red 

 or brown color changes. In the key, KOH-f means that a re- 

 action occurs; KOH— that it does not; and CaC102 is noted in 

 the same way. 



Key to Groups and Species 



Subgenus 1. CLADINA (Nyl.) Vain. Primary thallus crustaceous, soon dis- 

 appearing, rarely seen. Podetia slender, one to four inches tall in the species 

 in our range, much branched, arachnoid-tomentose, (like a spider's web, or 

 with fine down like hairs) without cortex (Latin bark or rind) or distinct 

 outer layer, except a "pseudo-cortex" of scattered or contiguous warty 

 excrescences, gonidia, green algal cells; tips of branches with two to eight 

 minute forks, usually brownish; apothecia small, circular, rarely seen. 

 The species in this subgenus are usually densely massed and tangled to- 

 gether, often in large colonies, and two or more species are often found to- 

 gether in the same colony. Terminal apices blunt. They are known gener- 

 ally as "Reindeer Mosses," because they are the principal food of reindeer 

 in countries near the Arctic Circle, such as Lapland, northern Scandinavia, 

 northern Russia and Siberia, and the support indirectly of several millions 

 of human beings who depend for food and clothing upon the reindeer. 

 They are generally of a grayish, or grayish green color, but may be brighter 

 green in the shade, or sometimes olive-tinted and are recognizable from 

 species of other subgenera from their massed, entangled habit. (Species of 

 C. furcata are also entangled but otherwise different.) They have been 

 used for human food, being ground up with rye or other cereal flour, and 

 this mixture is said to be nourishing and tonic in effect. 



Podetia in dense, irregularly entangled colonies 



Podetia often polytomous (many-branched) with whorls of three or more 

 branches surrounding gaping axils; outer podetial layers persistent. 

 Podetia ashy-gray, darker in old plants; or sometimes brownish or green- 

 ish; surface arachnoid, KOH-f-, yellowish. (PI. 1, f. 1.) 



1. C. rangijerina. 



Podetia yellowish-green, varying to gray, whitish or greenish; usually 

 more delicate than C. rangijerina; KOH — . Podetia straw-colored, 

 or greenish or grayish, with frequent sub-secund (on one side) 

 branches between the whorls of branches on the main axes, outer 

 branches often curving in one direction, apices nodding, with tips 



