236 MICHIGAN SURVEY, 1908. 



in diameter. Occasional in upland forest, in fact, fairly abundant in 

 places; also one of the trees to occur in crevices on the small rock 

 islands and along the rock shore, in which cases they have a decidedly 

 stunted appearance, and are often broader than high. I, 4; I, 6; II, 2; 



IV, 4; IV, 8; V, 6; V, 7; V, 8; V, 11; II, '04; V, '04. 



170. Jtmiperus tvcma Willd. Low evergreen shrub common on the 

 back heath zone and along the rock shore. It appears to follow 

 rather than to precede Juniperiis {procumbens) sahina with which it is 

 so commonly associated. A common form on the rock islands and in 

 the rock shore crevices. Also in the natural rock openings back from 

 the shore. I, 1 ; I, 2 ; I, 5 ; III, 1. 



171. Jimiperiis {procumb&ns) sal)ina L. Procumbent Juniper. A 

 very important pioneer on the rock islands and on the sloping rock 

 shore, starting as a crevice plant and sending out its dense prostrate 

 branches 6-10 feet. It offers a favorable place for wind blown material 

 which there accumulates, and this is of great importance for the 

 pioneer mosses which contribute so largely to the first humus soil. 

 Some most interesting examples of these pioneer stages were noted on 

 one of the low, nearly bare rock islands near the Rock Harbor light- 

 house, I, 1, and at V, 2, it was very abundant. 



Taxaceae — Yew Family. 



172. Taxus canadensis Marsh. Ground Hemlock, American Yew. 

 Everywhere abundant in the upland forests of the island. On account 

 of its low, spreading growth it forms one of the greatest impediments 

 in penetrating the island forests. The rankest growth was noted in the 

 lower forest region around Washington Harbor, where it attains a 

 height of four to five feet. I, 6; IV, 4; IV, 8; IV, 9; V, 4; V, 5; V, 7; 



V, '04. 



Salicaceae — Willow Family. 



173. Populus grandidentata Michx. Large-toothed Aspen. Princi- 

 pally along the Greenstone Ridge; not at all common as compared with 

 P. tremuloidss. 



174. Populus tremuloides Michx. American Aspen. Very common 

 on almost all parts of the islands where burnings and clearings have 

 occurred. This and the Betula papyrifera are the pioneer deciduous 

 trees in burned and cleared areas, where the two seem about equally 

 abundant, colonies of both being intimately associated. Younger and 

 older stands of this as noted along the Greenstone Ridge near Rock 

 Harbor, suggest the younger and older burnings bv the copper pros- 

 pectors. I, 1; I, 2; I, 3; I, 5; I, 6; I, 7; il, 1; II, 3; III, 4; IV, 5; IV, 

 9; V, 8; V, 9; V, 3; V, t; V, 5; V, 7; I, '04; III, '04. 



75. Populus Tialsamifera L. Balsam Poplar. One locality only; 

 head of Siskowit Bay. 



Betttlaceae — Birch Family. 



176. Corylus rostrata Ait. Beaked Hazel. Rocky slopes and sum- 

 mits of ridges. In thickets along the Greenstone. 



177. Betula papyrifera. Marsh. Paper, or Canoe Birch. Common 



