A total of 622 species and 10 subspecies and varieties of lichens, plus six species of lichenicolous fungi, are reported from Alaska, the Yukon, British Columbia, and Alberta, mainly along the Alaska Highway and some of its side roads in lichenologically badly known regions. Anaptychia bryorum is new to the North American Arctic, Gongylia nadvornikii, Lichenodium sirosiphoideum and Stereocaulon capitellatum are new to North America, and Degelia plumbea is new to western North America. Verrucaria lobata Thomson sp. nov. is described from British Columbia. New to Alaska are: Acarospora superfusa, Amygdalaria subdissentiens, Aspicilia ka- relica, A. quartzitica, Bacidia herbarum, Brigantiaea fuscolutea, Bryonora curvescens, Bryoria friabilis, Calicium abietinum, Caloplaca borealis, C. ammiospila, C. sinapisperma, Chaenotheca xyloxena, Cladonia macroceras, C. ochrochlora, Collema crispum, C. curtisporum, Cyphelium tigillare, Graphis scripta, Heterodermia speciosa, Hypocenomyce scalaris, Hypogymnia occiden- talis, Lecanora fuscescens, Lecidea erythrophaea, L. leptoboloides, L. lulensis, L. stenotera, Le- procaulon subalbicans, Leptogium cyanescens, L. teretiuscula, Melanelia sorediata, M. tominii, Nephroma helveticum subsp. sipeanum, Parmelia hygrophila, Parmeliella triptophylla, Pertusaria borealis, Phylliscum tenue, Physcia subtilis, Psora lurida, Psorotichia schaereri, Pyrenopsis poly- cocca, Usnea filipendula, U. wasmuthii, Verrucaria funckii, Xanthoparmelia somloensis. New to Alberta are: Biatora carneoalbida, Bryoria capillaris, Candelariella lutella, C. xanthostigma, Collema furfuraceum, Lecania dubitans, Lecidea albohyalina, L. myriocarpella, Phaeophyscia cernohorskyi, P. hispidula, Ramalina obtusata, Rinodina oregona. New to British Columbia are: Acarospora smaragdula, A. veronensis, Actinogyra muehlenbergii, Adelolechia pilati, Arthror- haphis alpina, Aspicilia anseris, A. caesiopruinosa, A. disserpens, A. fimbriata, A. ryrkaipiae, A. subplicigera, Baeomyces roseus, Biatora carneoalbida, Bryocaulon divergens, Bryonora castanea, Caloplaca ammiospila, C. tetraspora, Catapyrenium cinereum, C. compactum, Cladonia thom- sonii, Collema glebulentum, Kiliasia athallina, Lecidea alpestris, Leciophysma finmarkicum, Le- praria lobificans, Micarea crassipes, Pertusaria alaskensis, P. coriacea, P. gyalectina, Phaeophyscia hirtella, Polyblastia obsoleta, P. terrestris, P. theleodes, Rhizocarpon eupetraeum, R. eupetraeoides, P. umbilicatum fo. pseudospeireum, Rinodina occidentalis, Staurothele drummondii, Thelidium absconditum, Toninia tristis, Usnea angulata, U. capitata, Verrucaria devergens, V. rupestris. New to Yukon are: Actinogyra muehlenbergii, Amygdalaria panaeola, Aspicilia aliena, A. cingulata, A. disserpens, A. heteroplaca, A. ryrkaipiae, A. subplicigera, Bryonora castanea, Bryoria trichodes subsp. americana, Buellia elegans, Calicium viride, Caloplaca crenularia, C. discolor, C. invadens, C. nivalis, C. pyracea, Candelariella athallina, C. dispersa, C. lutella, Cetraria califomica, Cladonia alaskana, C. bacilliformis, C. borealis, C. luteoalba, C. sulphurina, Collema crispum, Dermato- carpon intestiniforme, D. miniatum, Ephebe hispidula, Lecanora atrosulphurea, L. boligera, L. gangaleoides, L. intricata, L. straminea, L. strobilina, Lecidea alpestris, L. lapicida fo. ochracea, L. subcandida, Lecidella carpathica, L. elaeochroma, L. wulfenii, Lepraria caesioalba, Leproloma cacuminum, Leptogium tenuissimum, Melanelia infumata, Micarea peliocarpa, Parmeliella arc- tophila, Peltigera kristinssonii, Polyblastia sendtneri, Psilolechia lucida, Psorotichia schaereri, Rhizocarpon alpicola, R. cinereonigrum, Rinodina bischoffii, Squamarina lentigera, Staurothele elenkinii, Stereocaulon saxatile.