430 Part IV. Chapter 2. 
beach is occupied by herbaceous plants, named the Croton- -Physalis Association. The 
most abundant is Croton maritimus which forms at places close associations Physalis viscosa, a 
perennial herb, is also frequent, while Ilex vomitoria (= I. cassine), Zanthoxylum, Juniperus vir- 
giniana, Opuntia pes-corvi form diminutive thickets only 1—3 decimeters high. The well known 
Euphorbia un Triodia purpurea, Solanum nigrum (a canescent form), Salsola kali, 
Teucrium Nashii, Chloris petraea, Panicum neuranthum, Cynodon dactylon. Rubus trivialis and 
Smilax bona-nox form ER ER element of the beaches. 
Dune Formation. A visit to the dunes of Virginia Beach by the writer 
confirmed in all essential details the observations of KEARNEY. The outer line 
of dunes is inhabited by certain hardy, strong-rooting plants, viz., Ammophila 
arenaria, with small colonies of Umiola paniculata, which entitely replaces 
Ammophila not far south of this region. /va imbricata forms roundish 
clumps on the outermost dunes. Panicum amarıum is associated with the 
above plants. 
Myrica Strip. This association is found on the middle open dunes (dune 
complex). Here Cakile americana and Salsola Kali occur, but are not cha- 
racteristic. Uniola and /va are absent, while on the other hand Ammophila 
and Panicum amarım are quite at home. Ammophila at times forms meadows 
like growths associated with scattered dwarf plants of Myrica carolinensis, 
QOuercus virginiana var. maritima, Rhus copallina, but Myrica forms dense 
thickets on the higher dunes to the exclusion of other shrubby species. 
Other shrubs, Sr oceur on the open dunes such as Prunus angustifolia, Salix fluviatilis, 
Quercus virginiana (= Q. virens), Baccharis re Cephalanthus occidentalis, Platanus 
occidentalis. Ah: live oak Quercus virginiana (= Q. virens) hardly occurs as a tree on the 
Virginia coast nor does it form thickets. Among the open dunes it is a straggling shrub usually 
wind swept. While the open dunes are not forested, scattered trees often grow upon them, 
i taeda usually advances farthest toward ch while Prunus serotina, Diospyros 
virginiana, Quercus falcata, Ilex opaca also occur. — Climbing plants according to my obser- 
vations abound in the middle dunes, Tecoma radicans, Vitis rotundifolia, V. aestivalis, Smilax 
bona-nox, S. TEE S. glauca, Lonicera ragt Rhus radicans, Amelopsis quinque- 
folia as lia — Beneath and among these the sand Hudsonia tomentosa, Lechea 
maritima, Fi teres, Rubus villosus. In the a er the bios ot Myrica carolinensis, not 
especially adapted to the dune environment, are Erigeron canadensis, Eupatorium capillifolium, 
Phytolacca decandra, Chenopodium anthelminticum. 
The open dunes of Ocracoke Island, North Carolina are occupied by sea 
oats, Uniola paniculata, associated with Muhlenbergia filipes, rather small 
plants of Yucca gloriosa, an occasional Yucca aloifolia, and Myrica car oli- 
nensis (Uniola-Yucca Association). Of secondary importance, Panıcum 
amarum, Spartina patens, Carduus spinosissimus, Oenothera humifusa, Croton 
maritimus are found. 
The tops of the low outer dunes on the Isle of Palms, South Carolina, according to 
COKER, are held by several sand-binding grasses, each of which seems to dominate particular 
elevations. Uniola paniculata, which is most abun dant, covers many of the ridges, Sporobolus 
virginicus has possession of others, and Panicum amarum and Spartina polystachya occur in con- 
siderable quantity. Here grow also Croton maritimus, Iva imbricata, Salsola kali, Euphorbia poly, 
gonifolia, Oenothera humifusa and Cenchrus tribuloides. At certain places the tide makes in 
between the outer ridges and floods the depressions behind them. Here Coker found Ipomoea 
