Arkansas-Louisiana District. 459 
charum, rubrum, A. dasycarpum, Fraxinus americana, Ulmus, Ostrya vir- 
giniana, Carpinus, Tilia, Cornus florida, Hamamelis, Negundo, Prunus serotina. 
The botanist might fancy himself in a northern forest but the presence of 
Magnolia grandiflora (= M, foetida), M. glauca (= M. virginiana), Persea 
carolinensis, Ulmus alata, Planera aquatica, Castanea pumila, Ilex_cassine 
convinces him that he is in the woods of the Arkansas-Louisiana District '). 
Pine Flat Formation. On the low almost perfectly flat lands of Arkansas- 
Louisiana, Mississippi and Texas the soils are of the same general character, 
but contain a large amount of clay and are, therefore, moist. Over consider- 
able areas on these flats, and especially in the open spaces, there is a dense 
and often quite high growth of grasses, ferns and ericaceous plants. Pinzs 
Taeda is the most common tree on the pine flats, and usually dominates. 
Pinus mitis (= P. echinata), is also well represented associated with Onercus 
alba, Q. oötusiloba, O. falcata, O. tinctoria while hickory is very scarce°). In 
this forest the pines stand high above the crown of the hardwoods, the latter 
forming a kind of undergrowth; but instead of occurring by single trees, the 
pines of these flats have a decided tendency to grow in large groups, or 
forming open groups and clumps are the oaks, gums and other hardwoods. 
In Texas the sandy ridges are covered normally with a pure growth of 
Pinus Taeda, while the flats are covered with a jungle of hardwood (oaks of 
several species) with some loblolly pine, a dense undergrowth of small trees, 
palmetto thickets and climbing vines looping over the branches of the trees. 
The forests on the pine flats are the densest in Texas with a very thick 
undergrowth of shrubs and small shade-loving trees. 
Pine Ridge Formation. The pine ridge forests occur on all the gently 
rolling or hilly portions of the country. The soils are deep, dry and rather 
compact loamy sands, usually with a slight admixture of clay and with an 
occasional bed of gravel or pebble. Pinus mitis (= P.echinata) forms a little 
more than fifty per cent ofthe total stand and is more than twice as abundant 
as Pinus Taeda. These pines tower high above the hardwoods, forming a 
second story above Ouercus alba, O. obtusiloba, Liquidambar styraciflua, 
alcata, ©. tinctoria. The undergrowth consists of species of Vaccinium, 
Kalmia latifolia, Persea pubescens and species of Smilar are found both in 
large and small groups and scattered openly and irregularly, while over 
large areas it is entirely absent, leaving the ground clear and bare under the 
mature trees. This type of shortleaf pine reaches by far its best develop- 
ment in the United States in northwestern Louisiana, southern Arkansas 
and northeastern Texas forming forests scarcely surpassed in their timber 
wealth. Its general distribution west of the Mississippi River is the country 
ı) E. N.P. In the Woods of eastern Texas. Garden and Forest V: 399. Aug. 24, 1892; 
see also Brav, W.L.: Texas Forests. The Forester VII: 31 June ı901. 
2) OLMSTED, FREDERICK E.: A working plan for forest Lands near Pine Bluff, Arkansas. 
Bureau of Forestry Bulletin No. 32: 22. U.S. Department Agriculture 1902. 
