Fink: LICHENS OF THE LAKE SUPERIOR REGION. 239 



comes somewhat common at the southwest and more so at the 

 northwest portion of the territory studied. It is one of the 

 southern intrusions which extend farther north at some distance 

 from hike Superior. Trees common farther south in Min- 

 nesota were noted north of the Mesabi range as ^lercus iiiacro- 

 carpa Michx. Crakcgus sp. and Fraxiniis sp. On Fraximis 

 was found Coniocvbc pallida (Pers.) Fr. which is common in 

 northeastern Iowa, and on the same host Pyrcmila leucophaca 

 (WaHr.) Kbr. also becomes common for the first time in this 

 northern area. Other lichens in the list of those found only 

 north of the Mesabi range or the Misquah hills could be se- 

 lected for special treatment, and on the whole this portion of 

 the Superior region shows a closer floral connection with central 

 Minnesota than does the most southern point reached, viz., Two 

 Harbors. 



The list of 258 species and varieties is a large one for a 

 rather limited area to yield, especially when it is stated that only 

 about 300 lichens have been listed for Minnesota, including 

 the present list. Yet the undisturbed portions of the region 

 are more remarkable for richness in individuals than for large 

 numbers of species. The Grand Portage area gave 132 species 

 and varieties and the Snowbank lake area 121. These two 

 areas are the ones best studied and are perhaps as thoroughly 

 explored as the Minneapolis area, which gave 113 species and 

 varieties. Both of the former two are like the latter small areas 

 and the comparison seems to indicate that the lake Superior 

 region is, area for area, only slightly richer in species than the 

 Minneapolis region. Professor L. H. Baile}^* found that the 

 species of Spermaphvtes and higher Ai'chcgoniatcs of the 

 region are only about one-tenth as numerous at lake Vermilion 

 as in similar areas six degrees farther south, and we should of 

 course expect some decrease in liehen species rather than an 

 increase in passing northward in the state. The reverse con- 

 dition existing is largely due to diverse conditions within the 

 region as to elevation and temperature and as to surface moisture, 

 all of which factors have been duly considered. The Snow- 

 bank lake area studied is a larger one than the Grand Portage. 

 About equal time was spent at the two places, and we did much 

 more of the time-consuming quantity-collecting at Grand Port- 



* Bailey, L. H., in Arthur, J. C. Report on botanical work in Minnesota in 

 18S6. Geol. and Nat. Hist. Surv. of Minn., Bull. 3:8. i O., 1887. 



