COLLEMATACEAE 1Z 



3. Algae Xanthocapsa 



a. Thallus crustose 

 (i) Spores i-celled 



(a) Hymenium covered with a mass of algae and hyphae 



Gonohymenia 161 



(b) Hymenium without epithecial mass 



X. Thallus pseudoparenchyraatic at margin 



Forssellia 161 

 y. Thallus nowhere pseudoparenchyraatic 



Psorotichia 161 

 (2) Spores 2-celled ; apothecia closed CoUemopsidium 161 



b. Thallus of one leaf, umbilicate, often lobed 



(i) Thallus pseudoparenchyraatic Anema 162 



(2) Thallus not pseudoparenchyraatic 



(a) Spores i-celled 



X. Hyphae loose, net-like at margin 



Thyrea 162 

 y. Hyphae perpendicular to the margin 



Jenmania 162 



(b) Spores 2-celled Paulia 163 



c. Thallus fruticose, branched, upright 

 (i) Thallus without layers 



(a) Asci 8-spored Peccania 163 



(b) Asci i2-many-spored *Pleoconis 164 



(2) Thallus layered, with a cortex Phloeopeccania 164 



n. Thallus with Nostoc ; spores clear Subfamily Collematae 168 



1. Apothecia with proper exciple only, biatorin 



a. Spores i-celled 



(i) Spores globose to fusoid, straight 



(a) Thallus crustose, scarcely gelatinous 



Leprocollema 170 



(b) Thallus scaly or dwarf fruticose, gelatinous 



Leciophysma 170 

 (2) Spores needle-shaped, twisted Koerberia 173 



b. Spores transeptate, 2-many-celled 



(i) Spores 2-celled; thallus without cortex 



Homothecium 171 



(2) Spores 4-8-celled ; thallus with cortex 



Arctomia 173 



2. Apothecia with thalline exciple , lecanorin 



a. Spores i-celled 



(i) Thallus scaly or dwarf fruticose; spores thin-walled 

 (.a) Thallus without cortex Physma 170 



(b) Thallus with pseudoparenchyraatic cortex 



Lemmopsis 171 

 (2) Thallus large-leaved ; spores thick-walled or mucose 



Dichodium 171 



b. Spores transeptate to muriforra 

 (I) Thallus without cortex 



