Perithccium (pi. Periihccia) A t'lask-shaped ascocarp enclosed 

 except for the apical pore (ostiole). It is usually more or less sunken 

 into the thallus (Fig. 10). 



PhycobioM (pi. Phycohioms) The algal member of the lichen 

 symbiosis (Figs. 9, 10). 



Pseudosepium (pi. Pseudoscpta) Appearing to be an mternal 

 wall but not composed of the same matenal forming the cell wall. 



Pycnidium (pi. Pycnidia) Small tlask-shaped to globular struc- 

 tures resembling penthecia but containing conidia instead of asci 

 and ascospores. 



Pyrencocarpous Having penthecia. 



PyrenoUchen (pi. Pyrenolichens) Lichen having penthecia 

 (Fig. 10). 



Reniform Kidney shaped. 



Reticulation A netlike appearance. 



Rimose Having minute cracks, usually referring to a form of 

 areolation. 



Saxicolous Growing on a rock or rock-like substrate. 



Sessile Not supported by a stalk. 



Simple Describing a spore having a single, undivided cavity. 



Siirediare Having soredia on the thallus. 



Sorediiini (pi. Soredia) A means of vegetative reproduction of 

 the lichen consisting of masses of hyphae and their associated algae 

 rupturing through and not covered by or containing corte.x (Fig. 9). 



Spray zone (pi. zones) That area above high tide that is struck 

 by drops of seawater resulting from the impact of waves on the 

 rocky shore under nonstorm conditions. 



Storm sprav zone (pi. zones) That area, above the usual spray 

 zone, that is sprayed with seawater only during a storm. 



Subconvex Barely curved outward. 



Subejfuse Having boundanes that are pooriy distinguished. 



Submerged Sunken entirely or mostly below the upper surface 

 of the thallus. 



Submoniliform Having constrictions at intervals giving an 

 appearance ncariy like a stnng of beads but not so pronounced. 



Tluilline margin (pi. margins) Apothecial nm having the same 

 composition as the thallus (Fig. 9). 



Tliallus (pi. Tlmlli) The lichen body containing both algal and 

 fungal components. 



Tiiberciilale Having a warty appearance. 



ILLUSTRATED KEY TO SPECIES 



The key is based primarily on charactenstics that can be observed with a dissecting microscope at 20 x magnification; in some cases 

 observation of spores with a compound microscope may be required. 



The vertical sections of perithecia of Verrucaria species illustrated in the key are typical sections. 



Because of the extreme degree of variation of species of manne lichens (especially of Verrucaria). identification of species from the key 

 alone should be regarded as tentative until the more detailed descnption in the Annotated List of Species is read. 



Five species from the Canadian Maritime Provinces are included even though at present they are not known from the eastern United 

 States. At least one species. Verrucaria maura. has not been collected in the eastern United States recently but the author has seen specimens 

 collected from the area over 50 yr ago. 



1 Thallus foliose (Fig. 9); always orange and KOH + purple 2 



1 Thallus crustose (Fig. 10) only in a few species orange and KOH + purple 4 



1 Thallus erect, fruticose, composed pnmanly of algal (Caloihnx) filaments; ascocarp penthecioid (Fig. II) Lichina conjinis 



Figure \\.— Lichina confinis. Scale is O.I 

 mm. 



2 (/) Thallus with .soredia mostly apical (Fig. 12l. thallus lobes finely divided l0,2-0,5 mm wide) . 



.Xanilioria cundclnria 



Figure 12.— Thallus iif Xantliuria candclaria. .Scale is 

 I nini. 



/r^^-^^i^^WwW 



^- 



2 (1) Thallus not sorediate, lobes w idcr than 0.? mm 3 



