Hill: PenoUcot Plants. 289 



more characteristic species of the rich woods — the eastern 

 deciduous forest. In such a forest the dominant trees are 

 Acer saccJiarion, Fa<jiis (irandifoJia, Beiula lutea, Tsuga 

 canadensis, and Finns Strohns, and associated with them 

 Hanidnielis virf/iniaiKt, Pruuus virr/iniand. Fraxinus ameri- 

 cana, with Acer riihrinn in swampy woods. 



Althouo-h these species occnr northward and even attain 

 considerable development in favorable localities, they are 

 very infrequent in the eastern Penobscot Bay region, an 

 area characterized by granites, schists and other rocks which, 

 owang to their high content of silica, yield a sterile or acid 

 rather than a basic soil. 



Even more noticeable is the absence of the herbaceous 

 types of the rich woods, the spring flowers common in leaf 

 mould. Among such forms which are entirely missing 

 from the eastern Penobscot Bay region may be mentioned 

 Erytlironiuni, Vvularia, Chnitonin, Asarnm, Hepatica, 

 ThaJictrum dioiciun, Saiiguinaria, Dicentra, Dentaria, 

 CaulopliyUuni, Mifella and Panax. These plants and many 

 others extend through Xew England as far as the Kennebec 

 River, leave the C(^ast at that point and follow up the limy 

 valley of the Kennebec to the rich Silurian limestone area 

 of northern Maine and eastern Canada. V ilnirnum denta- 

 tuni illustrates the distribution of the AUeghanian species, 

 which extend northward only to Xew Brunswick (Eig. ."> ). 



The absence of these plants of the AUeghanian forest from 

 the eastern Penobscot Bay region has two noteworthy excep- 

 tions. In the northern part of Deer Isle there exists an area 

 of serpentine and another of greenstone, a basic igneous rock. 

 In these areas the vegetation is entirely diflerent from that 

 of the surrounding country and consists of deciduous trees 

 and their characteristic undergrowth. Betuhi lutea., Fagus 

 grandifolia and Acer ruhruni predominate and in the deep 



