31 CLAYBERG— UPLAND SOCIETIES 1920] 



of Lake Michigan, and in the pine barrens of northern Michigan 

 as near as Wolverine in Cheboygan County. In general, the pine 

 occurs in three places: (1) on the high hills back of Walloon Lake, 

 (2) on Algonquin and Nipissing bluffs, and (3) as an early stage in 

 dune forest succession. 



The first location is a xerophytic open society of red pine sloping 

 southward to the lake. The herbage below is dominated by ericads 

 such as Caultheria procumbens L. and Vaccinium vacillans Kalm. 

 Occasional artificial clearings show an apparently succeeding stage 

 whose components are crowded and mainly of shrub size. Here 

 Comus (Baileyi ?) and Viburnum accrij'olium L. dominate. Follow- 

 ing this is an obviously secondary society (may be absent in the 

 primary series), taller than the preceding one and primarily Bctula 

 alba L. var. papyri/era Spach., with a mixture of Populus grandi- 

 dcntata Michx. and P. tremuloidcs Michx. Oak seems to follow. 



The second type, almost entirely white pine, shows the oldest 

 pines seen, growing on slopes approaching 45 , with sparse vegeta- 

 tion below characterized by Solidago racemosa Greene and SJicp- 

 Jierdia canadensis Nutt. The xerophytic conditions here obtaining 

 are indicated by leaves of Aralia nudicaulis L. 12 cm. across and 

 10 cm. tall, as well as by beds of Polytrichum commune L. Where 

 cleared, the succeeding thickets are white birch with some Prunus 

 pcnnsyhwiica L. f. and Amelanchier. 



The third type is a mixture of the two species, with white pine 

 dominating, but with other conifers present. Among the par- 

 ticularly characteristic undershrubs occurring are Corylus rostrata 

 Ait. and Rosa acicalaris LindL, while the herbage is largely of the 

 ericoid type. At Menonaqua the full series is seen, but north of 

 Harbor Springs erosion has eaten back into the pine society; the 

 xerophytic conditions resulting permit persistence of much of the 

 dune flora (telescoped succession). 



As at present limited, pine occurs here near water in positions 

 exposed to direct wind and of noticeably xerophytic nature. This 

 agrees with its probable status as a relict tree formerly covering the 

 upland. Transeau (24) believes conifers reached their present 

 distribution in the lower peninsula of Michigan by way of the lake- 

 shores. 



