KEY TO THE ARRANGEMENT. 13 



thalline one, margining or supporting a hymenium the 

 disk of which consists of naked spores. 



Fam. 1. SPILEROPHOREI. Thallus vertical, fruticulose. 



* SIPHULA. Apothecia unknown. Spermatia linear. 

 Thallus erect, sparingly branched or almost simple, 

 passing below into root-like branchlets by which the 

 lichen is attached to the substrate, densely cottony 

 within. 



58. SPH^ROPHORUS. Apothecia globose ; the proper ex- 



ciple reduced to a hypothecium, which is included in 

 a thalline receptacle, formed by the swollen tips of 

 the branches. S.pores spherical, simple, violet-black. 

 Thallus fruticulose, erect, densely cottony within. 



59. ACROSCYPHUS. Apothecia crateriform; a black 



proper exciple included in a clavate thalline recep- 

 tacle, formed by the swollen tips of the branches. 

 Spores ellipsoid, bilocular, brown. Thallus fruticu- 

 lose, erect, solid, the medullary layer at length more 

 or less compacted into cartilagineous cords. 



Fam. 2. CALICIEI. Thallus crustaceous, lobulate, or, 

 mostly, uniform. 



60. ACOLIUM. Apothecia crateriform, or now urn -shaped, 



sessile ; a black proper exciple, which is either naked, 

 or margined by an accessory thalline one. Spores 

 spherical and simple, or more often ellipsoid and 

 bilocular, rarely also quadrilocular, or even muriform- 

 plurilocular ; brown. Thallus crustaceous, rarely 

 lobulate, for the most part uniform. 



61. CALICITJM. Apothecia crateriform, stipitate; a naked, 



black proper exciple. Spores spherical, ellipsoid, or 

 oblong, simple, or bilocular, rarely quadrilocular, 

 brownish. Thallus crustaceous, or now almost obso- 

 lete, or (in parasitical species) none. 



