1914] ROBERTS— PLANT SUCCESSIONS OF HOLYOKE RANGE 443 



has passed in the ravine formation to permit the passing of the 

 succession to Fagus grandifolia. 



A young ravine on the south side in which cutting has long since 

 ceased contains many of the same forms showing a slow succession. 



THE BROOK 



The brooks are fast passing out of existence in the vicinity of 

 the range, so that mention is made only of the plants found in the 

 brook and on its immediate banks. The trees are Ulmus americana 

 and Acer rubrum; the shrubs, Alnus incana, Benzoin aestivale, Ilex 

 verticillata, Vitis Labrusca, Cornus stolonifera, and Dirca palustris; 

 the herbs, Thaspium aureum, Caltha palust/ris, and Symphoricarpus 

 foetidus. This is soon followed by a heavy growth of Carpinus 

 caroliniana, with Betula lutea, B. lenta, and Fraxinus americana. 

 These pave the way for oaks and hickories. 



Summary 



1. The region is a mountain range of trap rock, 



2. The climax forest of the region is of the beech-maple-hemlock 



type. 



may 



cliff 



Xerarch successions: (1) trap slope successions; (2) trap 



Hydrarch successions: (1) ravine successions; (2) brook 



successions. 



4. The terms initial and repetitive seem to be better 1 



mary and secondary in conveying the idea of often-repec 



cessions such as are found in a frequently deforested area. 



. 5. The east-facing and the south-facing trap slopes I 



same successions, Castanea dentata 

 climax. 



o x x ave the 



seems to present a temporary 



resents an initial succession in which 

 similar first stages, but the second 

 us and Finns resinosa. while on the 



north it is Tsuga canadensis. 



