Sections of fruiting structures may be made by hand with a 

 razorblade. The small size of the perithecia of many species of Ver- 

 ntcaria are difficult but not impossible to section. A double edged 

 razorblade. broken lengthwise, is most suitable. 



Microtome sections are complicated by the thin crustose nature 

 of the thalli and their adherence to the rock substrate. Furthermore 

 the involucrella of pyrenocarpous lichens are hard and brittle and 

 do not respond well to the usual paraffin imbedding techniques. 



Two techniques employing a freezing microtome are satisfac- 

 tory. One technique involves pouring a shallow layer of agar in a 

 small container The perithecium is moistened several times with 

 water containing a small amount of wetting agent, such as alcohol. 

 The perithecium and the subtending and surrounding thallus are 

 then scooped from the rock with a razor blade, taking care to lift the 

 entire penthecium from the rock. Faulty diagnosis will result if the 

 base of the perthecium is left on the rock. The thallus and perithe- 

 cium are then transferred to the surface of the agar A drop of melted 

 agar placed over the lichen material embeds it between the tw o lay- 

 ers of agar A cube cut from the agar is then placed on the freezing 

 microtome so that the thallus is perpendicular to the blade and the 

 vertical axis of the penthecium is parallel to the blade. The matenal 

 is then frozen and sectioned. 



The other technique involves commercially available synthetic 

 plastic matenals intended for embedding frozen sections. A mound 

 is built up on the microtome's object disc and frozen. A vertical face 

 is cut facing and perpendicular to the blade. The lichen material to 

 be cut is prepared as before and then pressed firmly against the 

 embedding matenal. The pressure melts the plastic and when the 

 pressure is released the plastic and embedding lichen fuse and 

 freeze solid. 



Both techniques have the disadvantage of leaving visible resi- 

 dues on the slide surrounding the sections. This is a problem only if 

 the slide is to be photographed. 



Some species of lichens give a color reaction to potassium 

 hydroxide. A drop of 10% solution is applied with a dropping 

 pipette or capillary tube, directly to the cortex, or to medulla 

 exposed by fragmentation or an incision. 



Santesson (1939) described a number of environmentally 

 induced morphological vanations in littoral lichens in general and 

 described in detail the variations of certain selected species. Both 

 Weber (1962) and Santesson (1939) have emphasized the impor- 

 tance of understanding the range of vanation induced by the 

 environment. 



The author has traced variations of single thalli from continu- 

 ous to areolate and from smooth to ridged. The author has also 

 observed variations of penthecia from sunken to prominently 

 raised on a single thallus. Even the darkness of the lower side of the 

 excipulum (inner lining of perithecium) is quite variable within a 

 single species. Shade modification is well known and predictable 

 among littoral lichens. Shade causes lighter pigmentation and 

 reduction in size and number of juga (black pegs, lumps, or ndges 

 protruding from the surface). Some species that are distinct in 

 appearance when growing in good illumination appear much less 

 distinct when growing in the shade. The distinguishing features of a 

 species are frequently reduced by the shade modification. As a 

 result there is considerable taxonomic confusion among the shade 

 modifications of Verrucaha striatiila, V. dilmarsica, and, to a 

 lesser degree. V. erichsenii. Too much stress can be placed on 

 perithecium size. Variations of perithecium size on a single thallus 

 beyond the range accepted in some taxonomic keys have been 

 observed. Thus the taxonomic character "perithecia slightly 

 smaller (or larger) than . . " should be regarded with suspicion. 



If one's study is restricted to a few specimens, it is easy to see 

 dichotomy among the species examined. As the number of speci- 

 mens increases, the kinds and degrees of variations also increase 

 and extreme forms are bridged by lesser variations. Since the litto- 

 ral environment is one of great physical contrasts and many micro- 

 habitats. it is not suprising that considerable taxonomically 

 confusing variations in the lichens have resulted. 



ECOLOGY 



Between low and high tide marks the rocks of the shore are 

 largely covered by macroaglae such as Fiicits sp. Among the hold- 

 fasts of such algae, the manne lichens compete for space with bar- 

 nacles. Bryozoa. and such algae as Hihienhrantia and 

 Lithothamnia . The lichen Anhopyrenia luilodyles often occupies 

 the shells of the barnacles with which the other lichens compete. 

 Penthecia. the cone-like fmiting stmctures of marine lichens, are 

 often seen protruding through the thalli of Hildenbrantia or Lilho- 

 ihamnia which have overgrown them. Such competition with the 

 lichen Vernicana mucosa has mixed results; either the lichen or the 

 alga may establish itself on top. Only the lichen genera Anhopyre- 

 nia. Sligmidium . and Vernicaria are found throughout this zone of 

 the shore. The Vernicaria species inaura and ceiilhocarpa do not 

 extend very far down into this zone. 



From the high tide mark upward for about 0.5 m is the barnacle 

 belt. The barnacles are so successful in the competition for space 

 that only their shells are available as a substrate for lichens. The 

 lichen Anhopyrenia haUxlytes is found here in pits dissolved into 

 the barnacle shells. 



Extending upward from the barnacle belt is the black belt pop- 

 ulated by various species of Vernicaria in competition with blue- 

 green algae, especially of the genus Calothrix. 



Investigators in northern Europe find a well defined orange 

 belt above the black belt and a white "RamaUna belt" above that. 

 In northeastern North America the orange belt is intermittent or 

 absent and the "Ramalina belt" is entirely absent. The orange belt, 

 where present, is compnsed of members of the genera Caloplaca 

 and Xanthoria. Lichina confinis. a black fmticose lichen, may be 

 found in this belt or extending down to the black belt. Various other 

 lichens may extend into the orange belt but in the few and incom- 

 plete orange belts encountered in northeastern North America by 

 the author, only Lecanora granlii. a gray cmstose lichen w ith cup- 

 like fruiting bodies, was found. Nothing above the orange belt was 

 considered in this study because it is the highest zone to contain 

 obligate marine lichens. 



The lichen flora collected at the northern end of the study 

 range was comprised of 22 species. At the southern end of the range 

 the lichen tlora was reduced to two species. In an attempt to explain 

 the distribution in terms of environmental cause, a multiple regres- 

 sion analysis was used to assess the impact of environmental factors 

 on the success of mdividual species and on the general diversity of 

 species. The environmental factors whose individual and interac- 

 tive effects were computed are: salinity, air and water temperatures, 

 solar insolation, and tidal range. No simple answers emerged either 

 for the success of any species or for general diversity. However, by 

 tallying the number of times that each environmental factor was 

 involved as one of the most important influences, the following fre- 

 quencies resulted: salinity, 21; insolation, 15; air temperature, 12; 

 tidal range, 7; and water temperature, 2. 



Where sufficient collections were made to provide adequate 

 data, vertical distnbutions of the various marine lichens were 

 graphed (Figs. 1-8). In these graphs the extent above mean high 



