Gulf Pine Barren-Strand District. 447 
Hammock Formation. There are more or less extensive tracts of black soil 
generally well drained skirting the lower river swamps or the low swamps of 
tide water. In these hammocks occur Ouercus virginiana (= O. virens), Mag- 
nolia sp. associated with Pinus caribaea, P. Taeda, Quercus laurifolia and 
O. aquatica, Fagus and many small trees and shrubs (as Osmanthus ameri- 
cana, Ilex, Myrica cerifera, Xanthoxylum, Prunus, Pirus, Crataegus, Chionanthus, 
Vaccinium arboreum. Vines of Vitis (Muscadinia) rotundifolia, Brunnichia cir- 
rhosa, Cissus and Smilax add to the maze of shrubs in the low hammocks. 
Apteria setacea is confined to the rich mold of the hammocks. 
The shady borders of the hammocks are marked by the presence of Sen microcalyx, 
Asarum arifolium, Zephyranthes atamasco, Lupinus villosus, Rhexia mariana, R. lanceolata, Agri- 
monia incisa, Amorpha glabra, Sanicula BEER Panicum gibbum, TEE irtellns Arun- 
etc. 
dinaria tecta e 
Where the hammocks merge into the alluvial lands, the soil becomes of a semi-swampy 
character. Here Halesia diptera, Cliftonia ligustrina, Cornus strieta ta, Cyrilla racemiflora, Ilex cassine, 
Adansonii, Andromeda nitida, Leucotho@ axillaris form the thicket, while as lianas occur- 
Der barbara, Wistaria frutescen eeiig sempervirens, Gelsemium semperviren 
ium !Aspidium) patens is confined er ively to the hammocks accompanied by Pol Bean 
acrostichoides, Pteris aquilina, Asplenium ebeneum, Woodwardia angustifolia and virginica, Lyco- 
podium cernuum deepest recesses of the hammocks on the limbs of old magnolia 
trees is found Epidendrum conopseum. 
Pine Barren Swamps and -Ponds. The swamps where the pine barren 
streams overflow their low banks of shifting sand and gravels have the same 
general tree covering as the pine barrens proper. When the soil is more 
deeply submerged, Chamaecyparis thyoides and Taxodium imbricarium prevail 
over the trees. Where the water is more shallow the botanist finds Osmanzhus 
americanus, Myrica inodora, Ilex ambigua while in many places between the 
trees are Mayaca Michauxü, Osmunda and Woodwardia. 
In the stagnant water of ponds flourish Nymphaca odorata, Brasenia 
peltata, Limnanthemum lacunosum, Cabomba caroliniana, Nuphar advena, 
Potamogeton, Utricularia, Sfirodela, Lemna. The main channel of pine 
barren streams is Infmbited by floating plants; other aquatics are Fontinalis 
disticha, Hydrochloa fluitans, Nuphar sagittaefolium, Utricularia purpurea, 
Orontium aquaticum and Scirpus cylindricus. The fresh water estuaries of the 
_ rivers are characterized by a submerged vegetation consisting of Zannichellia, 
Ruppia, Ceratophyllum, Potamogeton etc. 
In Texas the most conspicuous and constant plant of these ponds is the 
spider lily Hymenocallis occidentalis and rattle bush Daubentonia longifolia. 
The cane grass Arundo donax occurs as a river bank species along the Rio 
Grande to the mouth of the Pecos and above the canyon part of the latter 
stream it forms a dense bank jungle. 
Other herbaceous associations are found in the open river marshes. Reed-like grasses, 
large rushes and tall umbelliferous plants are characteristic of these swamps. Among these marsh 
plants are: Phragmites communis, Spartina polystachya, S. cynosuroides, ica, Seirpus 
lacustris, 8 Olneyi, S. Anviatils, Cladium effusum, Typha latifolia, Cicuta maculata, Tiedemannia 
