9 (4) Spores one-celled 11 



9 (4) Spore^ more than one-celled 10 



10 (9) Growing on ihallus of Vernicahiw: paraphyses gelatinizing, spores 10-15 x .^.S-S/jni with 4 locules and distinct cen- 



\n\ septum (Fig. 21 ) Stigmidium marinum 



Figure 21. — Spore of Sligrrudium 

 marinum. .Scale is lO/im. 



10 (9) On barnacles or rock; thallus scant to evidently lacking; paraphyses persistent, spores 9-20 x 4-7^in with two locules 



(Fig. 11) Anhopyrenia halodytes 



Figure 22.— Spore of Anhopyrenia halodytes. 

 Scale is lO/im. 



1 1 (9) Thallus with pegs and/or ridges present (Fig. 23) 16 



Figure 23.— a. Thallus with pegs. b. Thallus «ilh ridges. Scale is 1 mm. 



a I ♦ b 



1 1 (9) Thallus smooth; pegs and ridges lacking 12 



12 (//) Thallus areolate (di\ided mto fields by fissures. Fig. 24 1 15 



Figure 24. — Areolale thallus. Scale is 

 1 mm. 



I ( 



12 (//) Thallus continuous or discontinuous but not areolate (Fig. 25) 13 



-> .' 



c? 



Figure 25.— a. Continuous thallus. b. Discontinuous thallus. Scale is 

 I mm. 



