THE DETERMINATION OF LIC1[ENS IN THE FIELD 17 



7. Sp. brown, 2 in ascus. Pits shallow ... Microthelia dispora. 

 Sp. colourless, usu. 8 in ascus. Pits often 



deep 8. 



8. Frequent plant of calcareous rocks. Algal 



cells green. Perithecia minute. Sp. 



about 30 X 15 ja Thelidium immersum. 



Eare plants, often on shells. Algal cells 

 Trentepolilia. Perithecia minute. Sp. 

 about 18 X 6 /x Arthopyrenia foveolata {h). 



{cC) V, rupestris, V. Integra, V. dolomiticci, V. marmorea, and 

 V. 'parva. When the th. of V. muralis is evanescent the perithecia 

 may leave slight pits. 



{h) A. litoralis and A. saxicola may have their perithecia in 

 shallow pits. 



F. ThALLUS CliUSTACEOUS oil WANTING. SPOEES BECOMING 

 FREE IN THE APOTHECIUM. CONIOGARPINE^. 



1. Ap. stalked. Sp. dark or yellow. Habitat 



various («) 3. 



Ap. sessile or almost so. Sp. dark. On 



wood or parasitic on other lichens 2. 



2. Sp. septate (usu. 1 -septate). Ap. sessile 



with thalline margin. On wood (except 

 C. stigonella^ which is parasitic on Fer- 



tusaria) Cyplielium {h). 



Sp. simple. Ap. sessile (or shortly-stalked), 

 without thalline margin. Usu. parasitic 

 on Pertusaria (c) Sphinctrina. 



3. Sp. spherical, simple, ^^ellowish in the mass . Coniocybe. 



Sp. spherical, simple, dark in the mass Chaenotheca. 



Sp. oblong, 1 -septate, dark Calicium. 



Sp. oblong, 3- or more-septate, dark Stenocybe. 



(«) The habitat is usually trees or worked wood. Conioci/he 

 furfuracea sometimes occurs on ground, decaying mosses, or rocks. 

 Calicium arenarium is present on the yellow th. of the saxicolous 

 Lecidea lucida, and Stenoci/be trajecfa Nyh { = S. septata Eehm.) 

 may be parasitic on the th. of Thelotrema lepadiiium and Graphis 

 elegans. Calicium dehile has been recorded from rocks. 



{h) C. notarisii has the sp. 1-5-septate and slightly muriform. 



(c) S, hylemorensis is found on Lecanora. S. microcephala 

 Koerb. { = S, anglica Nyl.) is found on bark and wood. 



Gr. GEAPHIDINEiE. ThALLTJS CliUSTACEOUS OR WANTING. TlIECIA 

 ELONGATE OR IRREGULAR OR RADIATE. («) AlGAL CELLS USU. 



Trentepoulia. 



1. Th. corticate above, determinate, white, C-\- 



red. On rocks Diriiia. 



Th. not corticate above. On rocks, wood, 



etc 2. 



Journal of Botany, 1922. [Supplement I.] c 



