Hill: Penobscot Plants. 295 



The most noticeable of these absences, that of the species 

 characteristic of rich soils, has already been allnded to. 

 Such families as the Banunculaceae, Cruciferae, Saxifraga'- 

 ceae, Leguminosae and Scropliukiriaceae, to which many of 

 onr commonest species of the rich woods belong, are scarcely 

 represented save by introduced species. The paucity of 

 these Alleghanian plants in our region is brought out more 

 clearly by a comparison with a region where environmental 

 conditions are more favorable. Kennedy's Flora of Wil- 

 loughby/ a limestone area in northern Vermont, lists 690 

 plants as against 736 in eastern Penobscot Bay. Of these 

 690 nearly 300, or 40 per cent, are lacking in our region, 

 which is characterized for the most part by neutral and acid 

 rather than basic soils. 



A second noteworthy absence is that of species present on 

 the mainland to the east and west and even on Blount Desert 

 but which have failed to reach the islands of Penobscot Bay. 

 As examples may be cited : 



Agropyron caninum Anemone qwnquefoJia 



Triglochin palustris Chrijsosplenium americanum 



Scirpus caespitosus Poly gala pauci folia 



Carex norvegica Ludvigia palusfris 



Carex lenticularis CliimapJtila umbellafa 



Juncus fliforniis Lobelia cardinalis 



These species it will be noted are not restricted to any one 

 group, but include northern as well as southern forms. It 

 is obvious from this fact, and from the circumstances of their 

 occurrence in nearby localities on the mainland, where soil 

 and climatic conditions are similar to those in Penobscot 

 Bay, that some factor other than the character of the habitat 



1. Kennedy. Flora of Willoughbv, Vermont. Rhodora 6: 94-134 

 (1904). 



