16. PELTIGERACEAE 



Thallus squamulose or foHose ; dorsi-ventral ; a well-developed cortex 

 on one or on both surfaces, definite algal and medullary layers ; attached to 

 the substratum by rhizoids. Apothecia round or irregular, marginal on 

 either the upper or the lower surface, or scattered on the upper surface, 

 adnate; proper margin present, thalline margin absent; asci 2-8-many- 

 spored; spores hyaline or brown, 1-7-septate. Cephalodia present in some 

 genera. 



Alga Palmella, Dactylococcus, or Nostoc. 



A. Apothecia marginal. 



B. Apothecia on the upper surface, spores hyaline 30. Peltigera 



B. Apothecia on the lower surface, spores brown or brownish. 



29. Nephroma 



A. Apothecia scattered on the upper surface 28. Solorina 



28. Solorina Ach. Kgl. Vet. Akad. Nya Handl. 228. 1808. 



Thallus foliose, sometimes squamulose, differentiated into a thin or thick 

 pseudoparenchymatous upper cortex and a poorly developed lower cortex, 

 with well-defined algal and medullary layers; loosely attached to the sub- 

 stratum by rhizoids. Apothecia round or irregular, partly immersed to 

 adnate; proper margin thin, concolorous with the thallus, sometimes dis- 

 appearing, thalline margin absent; hypothecium hyaline; paraphyses sep- 

 tate, unbranched, rather thick; asci 2-8-spored; spores brown, 1 -septate. 



Alga Palmella or Nostoc. 



A. Thallus saffron yellow or reddish orange below 1. 5". crocea 



A. Thallus pale gray or brown below 2. S. saccata 



1. Solorina crocea (L.) Ach. Klg. Vet. Akad. Nya Handl. 228. 1808. 

 Lichen croceus Linn. Sp. PI. 1149. 1753. 



Thallus foliose, Madura brown (M.&P.) or various shades of brown, 

 small to medium sized, orbicular, lobes short and broad, smooth, margins 

 wavy, usually imbricated; below saffron-yellow (M.&P.) or orange-rufus 

 (M.&P.) with brownish veins, rhizoids sparse, clustered. Apothecia scat- 

 tered, 2-10 mm. in diameter, roundish, adnate; disk old Burgundy color 



(42) 



