86 OmDE TO THE STUDY OF LICHENS. 



5. Sphcerophorus. 



This genus represents the highest development .of 

 the Caliciaceae, there is a wide gap between it and 

 Acolium. The links are entirely wanting in the 

 United States. It has been questioned whether 

 Sphaerophorus belongs to the Caliciaceae ; concerning 

 this there can, however, be no doubt. The apothecia 

 and spore characters are the same as those of the other 

 genera. 



The thallus is fruticose, quite large, of a rigid car- 

 tilaginous consistency ; color brown or reddish-brown. 

 The apothecia are globose and terminal on the branches 

 of the thallus ; they open by terminal chinks, thus set- 

 ting free the simple dark spores. The spores are char- 

 acterized by the irregular dark blue exine (exosporium) 

 which is readily removed. 



1. Sphcerophorus fragilis. Thallus-lobes cylin- 

 drical, smooth, color somewhat variable, from light 

 gray, brownish to dark, dichotomously branching, ends 

 of branches usually with numerous short lobes, tips 

 blunt or rounded. Usually sterile or apothecia few, 

 shrunken. Disk black. Entire apothecium easily re- 

 moved at the hypothecial zone. Spores elliptical, 

 simple, dark-brown exine, 15/x X 10/>i- 



2. Sphcerophorus glohiferous. Thallus lobes cylin- 

 drical, variable in length, usually of uniform brown 

 color, especially in old herbarium material. Branch- 

 ing dichotomous. Apothecia globoid, opening by 

 chinks or pores. Spores spherical, simple, blue-black 

 exine easily removed by pressure, 12/x X IV* 



