GENERA AND SPECIES. 187 



dark to nearly black. Spermagonia sometimes numer- 

 ous. 



Considerable material from widely different localities 

 has been examined, but no apothecia have been found. 

 It is perhaps always sterile in this country. Lindsay 

 and others report it as apothecia-bearing in Europe. 

 Bornet, the noted French lichenologist, states that it 

 is dioeciaus, that is, the male reproductive organs (sper- 

 magonia) occur upon one plant, while the female or- 

 gans (apothecia) occur upon another plant. It seems 

 to be an undecided question whether Ephehe puhescens 

 is a genuine lichen ; it is perhaps only an alga (^S. pul- 

 vinatus) parasitically associated with fungi (sperma- 

 gonia and apothecia). 



Tuckerman reports two more species, E. mammiUo- 

 sum and E. solida, both of which are said to resemble 

 the one described. 



2. Lecothecium. 



Thallus crustose to perhaps minutely foliose, dark, 

 closely adnate to substratum. The algoe are bluish- 

 green and occur in chains {Rivularia nitida). 



The apothecia are of medium size, discoid, sessile or 

 partially immersed. The hypothecium is usually dark, 

 sometimes blue-black. The spores are few, variable 

 in size and form, due to the fact that but few attain 

 maturity. Wlien mature they are oblong, colorless, 

 four-celled. 



Only a few representatives are known in this coun- 

 try, they occur in the arctic regions and the north 

 temperate zone. They grow upon rock or sandy 

 soil. 



