&) 
Development of the Vegetation of New York State 73 
Growing season 160 to 180 days (Lower Hudson region ; 
Erie and Ontario basins). “ Thinned out” at low elevations 
of 150 days growing season. (Apparent exception — see 
Fig. 2. — in ease of Delaware, Susquehanna and Alleghany 
valleys ¢) 
C. Dominance of Sugar Maple, Becch, Yellow Birch, Hem- 
lock and White Pine Mixed Forest. Alleghany-Transition 
Forest Zone. 
Indicator species. 
White pine —=(Pinus strobus L.). 
Hemlock (Tsuga canadensis (L.) Carr.). 
Hop hornbeam Ostrya virginiana (Mill.) Willd.). 
Blue beech. Water 
I I Al 
_ 
beech =(Carpinus caroliniana Walt.). 
Yellow birch =(Betula lutea Michx. f.). 
Beech =(Fagus grandifolia Ehrh.). 
Witch hazel =(Hamamelis virginiana L.). 
June berry =(Amelanchier canadensis (L.) Medic.). 
Wild black cherry (Padus (Prunus) virginiana (L.) 
Mill.). 
Acer saccharum Marsh.). 
Acer rubrum lL.) Notably in swamps. 
Acer pennsylvanicum L.). Zone D? 
Acer spicatum Lam.). Zone D? 
Tilia americana L.). 
Fraxinus americana L.). 
Sugar maple 
Red maple 
Striped maple 
Mountain maple 
Basswood 
White ash 
A a ee aaa 
HE WL TT Al 
Of special note is, one may well say, the maximum oc- 
currence of the forest floor herbaceous growth-forms which 
comprise especially the popularly favorite spring woodland 
flora of the eastern half of the continent generally. Their 
relation to the deep, warm, soil blanket of climax forests 
seems to render them less susceptible to the limiting factor 
of winter cold or other expressions of the temperature factor 
(daily extremes, ete.). Hence one finds such elements ex- 
tending in force even into the more boreal conditions of the 
Adirondacks, though becoming notably supplanted at length 
by more strictly boreal species — see under Zone D. Fam- 
iliar species in this connection are: 
Virginia grape-fern, hay-scented fern, christmas fern, 
evergreen-wood fern, maiden-hair fern, plantain-leaved sedge, 
