372 43. BUELLIACEAE [ 169. Buelliella 



169. Buelliella Fink.* 



Parasitic on other lichens and the thallus invisible but probably parasitic on the 

 algae within the lichen host; apothecia adnate to sessile, the disk flat to convex, 

 commonly black, the exciple colored like the thallus, sometimes disappearing ; hypo- 

 thecium brown to black; hymenium hyaline to brownish above; paraphyses rarely 

 branched, sometimes enlarged and brownish toward the apex; asci clavate or 

 cylindrico-clavate ; spores 8, brown, 1 -septate, oblong-ovoid to ellipsoid or oblong. 



The algal host is Protococcus. 



A. Exciple persistent or tardily disappearing 



B. Apothecia reaching 0.7 mm. across 2. B.inquilina 



B. Apothecia not more than 0.4 mm. across 



C. Spores 9-12 X 4.5-6.5 m 1. B. saxatilis 



C. Spores 12-15 X 5-6 p 6. B. Nuttallii 



A. Exciple commonly disappearing 



B. Apothecia not more than 0.2 mm. across 



C. Spores 8-12 X 4-5 /i 7. B.Usneae 



C. Spores 14-16 X 5-7 fi 4. B.minimula 



B. Apothecia reaching 0.5 mm. across 



C. Spores 10-15 X 3.5-6 fi 5. B. Parmeliarum 



C. Spores 16-18 X 6.5-S.5 n 3. B. Trypethelii 



1. Buelliella saxatilis (Schaer.) Fink n. comb. 



Calicium saxatile Schaer., Naturv. Anzeig. Schw. Ges. 5:35. 1821. Buellia 

 saxatilis (Schaer.) Koerb. 



Thallus immersed in that of the host and invisible; apothecia minute to small, 

 0.2-0.4 mm. across, subsessile, the disk flat to slightly convex, black, the exciple 

 thick, brownish black; hypothecium dark brown; spores ellipsoid, 9-12 X 4.5-6.5 /x. 



On Baeomyces byssoides, Vermont and Minnesota. 



2. Buelliella inquilina (Tuck.) Fink n. comb. 



Buellia inquilina Tuck., Lich. Calif. 32. 1866. 



Thallus immersed in that of the host and invisible; apothecia minute to small, 

 0.2-0.7 mm. across, adnate to sessile, the disk flat to convex, brownish black to 

 black, the exciple black, prominent, but finally disappearing; hypothecium brown; 

 spores ellipsoid, 10-17 X 5.5-8 p. 



On species of Pertusaria and Lecanora, from Pennsylvania to South Carolina, 

 and westward to Minnesota and Texas. 



3. Buelliella Trypethelii (Tuck.) Fink n. comb. 



Buellia Trypethelii Tuck., Syn. N. A. Lich. 2:106. 1888. 



Thallus immersed in that of the host and invisible; apothecia minute to small, 

 0.2-0.4 mm. across, sessile, sometimes becoming oblong-difform, the disk flat to 

 slightly convex, black, the exciple thin, black, and disappearing; hypothecium 

 blackish brown; spores oblong-ovoid, 16-18 X 6.5-8.5 /x. 



On Try pet helium carolinianum, Florida. 



4. Buelliella minim ula (Tuck.) Fink n. comb. 



Buellia minimula Tuck., Syn. N. A. Lich. 2:106. 1888. 



Thallus immersed in that of the host and invisible; apothecia very minute, 

 0.07-0.12 mm. across, adnate, the disk flat, brownish to black, the exciple thin, 

 blackish, and disappearing; hypothecium brown; spores oblong-ovoid, hyaline to 

 brownish, 14-16 X 5-7 yu. 



On a species of Pertusaria, Florida. 



5. Buelliella Parmeliarum (Sommerf.) Fink n. comb. 



Lecidea Parmeliarum Sommerf., Suppl. FI. Lapp. 176, 177. 1826. Buellia Parme- 

 liarum (Sommerf.) Tuck. 



* Buelliella Fink gen. now A Buellia De Not. thallo parasitico et inconspicuo, in hospitis 

 thallo immerso differens. 



