® 
466 Part IV. Chapter 2. 
therefore, represent the main constituent species of the present- day forest with 
the Dössihle introduction of a few additional species that migrated north from 
the denser forest that clothed the valleys and slopes of the southern Alleghany 
Mountains. 
The dominant trees of the forest that covered and still covers in patches southeastern 
Pennsylvania parts of Delaware?) is composed of the following species: tulip-poplar, Liriodendron 
re - Er Castanea dentata (= Castanea sativa var americana); black walnut, Juglans 
nigr ak, Quercus rubra; white oak, Q. alba; scarlet oak, Q. coceinea; chestnut oak, Q. rinus; 
Boasich 2 Q. falcata (= Q. digitata); beech, Fagus americana (= F. ferruginea); Carya alba 
(= Hiecoria =. ackberry, Celtis occidentalis; butternut, Juglans cinerea; sweet gum, Liqui- 
dambar styraciflua; persimmon, Diospyros virginiana; white elm, Ulmus americana; white ash, 
Fraxinus a: wild red cherry, Prunus pennsylvanica; pignut, Carya porcina (= Hicoria 
glabra); silver maple, Acer saccharum; red maple, Acer rubrum; buttonwood, Platanus ocei- 
dentalis; small-fruited hickory, Carya microcarpa. = Hicoria microcarpa) and ironwood, Ostrya 
ginia 
alluvial soils of the creek and river bottoms. Thus the black-walnut, tulip-poplar, white elm, 
rege red maple and silver maple reach their best development on such soils. The w hite 
ash, chestnut, etc. seem to grow equally. well in the drier upland soils. ‘The red 
nn er virginiana, on the other hand, seems to be confined to barren places and to 
rocky 'outcrops, while the trees that grow ne | the banks of the streams within the region 
comprise the red maple, Acer rubrum, the hornb mei caroliniana; swamp oak, Quercus 
palustris; buttonwood, Platanus oceidentalis; bo zealde , Negundo aceroides (= Acer negundo); 
beech, Fagus americana; ‚Sassafras offieinale and er birches and willows. — ji forest in 
the neighborhood of Washington, DC. ”) is essentially similar; the dominant trees : Quereus 
alba, Q, Prinus, Q. coceinea, Q. palustris, Q. falcata, Carya tomentosa (= Hicoria Se Lirioden- 
don en Among ‚other common trees here are Castanea, Fagus, Acer rabrum, Platanus 
oceidentalis, Betula nigra (along rivers), Ulmus americana, Nyssa multiflora, Liquidambar styraci- 
flua with admixture in groves or ‚singly of Pinus inops, P. rigida, P. mitis. 
The trees form a Re canopy, and shade the forest floor, so that the se- 
condary species, shrubs, sapling trees and herbs, must be tolerant of such 
dense shade. The dominant trees reached their great size in the primeval 
forest, for some are left which attest this. Thus are found white oaks six to 
eight feet in diameter, buttonwood trees six feet across, white pine five feet in 
diameter, beeches four feet, black walnut trees four to five feet, tulip-poplars 
six feet, sassafras trees two and a half. 
The secondary species, tolerant of the shade, are the dog-wood, Cornus (Cynoxlon 
florida; red mulberry, Morus rubra; service berry, Amelanchier canadensis; bladdernut, Staphylea 
trifolia; Judas-tree, Cereis canadensis; hazel, Corylus americana; witch-hazel, Hamamelis virginiana 
and striped maple, Acer ARREEUEORER, while as shrubs oeeur smooth alder, Alnus serrulata 
(= A. rugosa); spice-bush, Lindera Benzein; dockmackie, Viburnum acerifolium; arrowwood, Vibur- 
num dentatum; stagbush, Viburnum prunifolium; strawberry bush, Euonymus americanus, waho00, 
Euonymus atropurpureus, and pinxter flower, Rhododendron sadiflormen (= Azalea nudiflora); 
rt) STERRETT, W.D.: Report on Forest Conditions in Delaware. rss 82, Delaware Col- 
lege nn Enge: Station. December 1908, pages 1—58 with map and 10 figures 
2) WARD TER F.: Guide to the Flora of Washington and Vicinity. ateie of the Unk 
ted States wer Museum, No. 26. 1881. 
