19 (/7) Juga raised or immersed, appearing as usually irregular and often branched ridges often merging with or continuing 

 over penthecia, if immersed appearing as black spots when wet; thallus blackish-brown, becommg brown to 

 amber and translucent when wet; perithecia spreading and irregular at base, up to 0.3 min diameter (Fig. 36); 

 spores 8-9 x 4.5-7/im Verrucaria erichsenii 



Figure 36.— a. Vertical section of perithe- 

 cium. Scale is 0.1 mm. b. Thallus of Verruca- 

 ria erichsenii. Scale is 1 mm. 



20 (/6) Perithecia immersed, spores 9-12 a 5-6;(m; juga appearing as long sharp black ridges on borders of thallus, some- 

 times extending across thallus, fissures occasionally develop along juga and simulate areolation; thallus usually 

 green to cream colored (Fig. 37) Verrucaria degelii 



Figure 37.— a. Vertical section nf perithecium. Scale is 0.1 mm. b. Thallus of Verrucaria degelii 



Scale is 1 mm. 



20 {16) Perithecia raised and prominent (Fig. 38) 21 



Figure 38.— Thallus with prominent raised 

 perithecia. 



21 {20) Juga inclosing lenticular areas giving appearance of npples on water, continuing on pentheciutii to form reticular 



pattern. Perithecium elevated, often craterous (Fig. 39); spores 9-20 x 4-7.5;tni Verrucaria amphibia 



Figure 39. — a. Vertical sectit)n of perithecium. Scale is 1 mm. b. Thallus of Verrucaria amphibia. (Thai 

 us thinner than Fig. 34b. Cracks developed in storage.) Scale is 1 mm. 



21 [20) Juga scattered, not inclosing lenticular areas 22 



13 



