GENERA AND SPECIES. 147 



they are usually discoid, irregular in outline, sessile or 

 adnate upon the thallus. The disk is usually flattened, 

 margin only slightly elevated. Hypothecium is color- 

 less. 



The spores are long, acicular, pointed toward one 

 end, curved, undulate or twisted, colorless, five to 

 seven-celled. The spores are very characteristic, and 

 when once seen are not likely to be mistaken ; they re- 

 semble most nearly those of Bacidia. 



I'he species occur upon rock, trees, earth, logs, etc. 

 They are somewhat northern in their range and prefer 

 mountainous districts. 



1. HcBmatomma punicea. Thallus areolate to warty, 

 greenish-gray. Apotliecia small. Disk bright reddish- 

 brown. Spores acicular, colorless, five'to seven-celled, 



2. Hcematomma ochrophcea. Thallus thick, warty, 

 not fissured, grayish-green, white internally. Apothecia 

 small to medium. Disk pale to dark brown. Spores 

 colorless, indistinctly five to seven-celled, curved, 

 49/x X 4.5/x. 



S. Hcematomma ventosa. Thallus very thick, deeply 

 fissured; surface areolate, warty; yellowish-green to 

 dirty green above, white within and beneath. Apothecia 

 medium to large, spreading, margin irregular in out- 

 line and somewhat lobulate. Disk reddish-brown. 

 Spores five to seven-celled, colorless, curved, thinner 

 toward one end, 37/x X 2/x.. 



The so-called L^'Cidea parasitica (perhaps a fungus) 

 is often parasitic upon this plant. H. ventosa is closely 

 related to the foreign Lecanora esculenta already men- 



