76 LECIDEACEAE 



y. Algae Palmella Nephroma 193 



b. Thallus minute, small triangular scales radiating from the apothecium 



(1) Asci 8-spored; spores brownish, 4-6-celled 



Asteristium 191 



(2) Asci many-spored ; spores clear, 2-celled 



Solorinella 192 



Family 40. LECIDEACEAE 

 Zahlbruckner 114, 129, 138, 144 

 Thallus firm, not gelatinous, crustose, scaly or foliose, exceptionally dwarf 

 fruticose, with rhizoids or a navel in the larger forms, with or without cortex; apo- 

 thecia superficial or somewhat sunken at first, with a characteristic proper exciple, 

 very rarely lacking, but without a thalline exciple. The absence of the latter dis- 

 tinguishes this family from the Parmeliaceae. 

 I. Thallus uniform or crustose 



1. Algae Chroolcpus or Phyllactidium Subfamily Lecanactidae 114 



a. Proper exciple lacking, or rudimentary and lateral 



(1) Spores transeptate; exciple mostly absent 



Schismatomma 115 



(2) Spores muriform; exciple thin, complete 



Melampydium 116 



b. Proper exciple well-developed, carbonous 



(1) Spores 2-celled Arthoniactis 115 



(2) Spores 4-many-celled Lecanactis 115 



(3) Spores needle-shaped *Scolecactis 115 



2. Algae Pleurococcus or Palmella Subfamily Lecideae 129 



a. Thallus uniform-crustose, loose, without cortex : spores clear, fusoid, 4-celled 



Pilocarpum 116 



b. Thallus typically crustose, firm 



(1) Asci 1-8-spored, rarely 16-32-spored 



(a) Spores i-celled 

 x. Spores clear 



(x) Asci 1-2-spored; spores large, thick-walled 



Mycoblastus 133 

 (y) Asci 8-spored 

 m. Exciple black, carbonous Lecidea 130 



n. Exciple clear or colored, not carbonous 



Biatora 132 

 (z) Asci 16-32-spored *Pleolecis 132 



v. Spores brown Orphniospora 133 



(b) Spores 2-celled 

 x. Spores clear 



( x ) Paraphyses simple 

 in. Spores thick-walled, large Megalcspora 134 

 n. Spores thin-walled, small 



(m) Thallus with cortex *Diphloeis 136 



(n) Thallus without cortex 



