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Vol. 41 No. 4 




APRIL, 1914 

The " Pocosin " of Pike County, Alabama, and its bearing on certain 
problems of succession 

Roland M. Harper 
(with four text figures) 

In eastern North Carolina, where the geographical term 
" pocosin" is used more frequently than in all the rest of the world, 
it means a flat wet place with peaty soil, usually remote from large 
streams, with a scattered growth of trees, mostly Pinus serotina, 
and a dense shrubby undergrowth.* In South Carolina and 
Georgia this term is almost unknown, f but it reappears in the 
coastal plain of Alabama, with a very different meaning. 

In a chapter contributed by E. Q. Thornton to Prof. Tuomey's 
second report on the geology of Alabama, published in 1858 (p. 
244), we find the following interesting bit of information: 

"East of this place [Troy] is a small scope of country of peculiar appearance, 
known as the Pocosson settlement. The vallies, which have the rank luxuriant 
growth of a swamp, are surrounded on three sides by a ridge of snow-white sand, 
which seems to have been heaped up by the tides on a sea-shore. The only occupant 
of the hills is a scrubby oak covered with long moss. The soil is exceedingly un- 
productive, and soon wears out by cultivation." 

*See Bull. Torrey Club 34: 361-363. 1907; C. A. Davis, N. C. Geol. Surv. 
Econ. Paper 15: 149-150. 1910; L. W. Stephenson, N. C. Geol. Surv. Vol. 3: 280. 
pi. 24B. 1913. 

t Miss E. F. Andrews (see Torreya 13: 64-66. 1913) wrote me early in 1913 that 
she had heard the term applied to certain "large flowery swamps" in the vicinity of 
Albany, Georgia, where she used to live; and the government soil survey of Dougherty 
County, Georgia, published in October, 1913. indicates a "Percosin Creek" a few 
miles west of Albany, but says nothing about any application of the name to vegeta- 
tion. Still more recently (March, 1914) I have heard of an occurrence of the term 
in West Florida. 

[The Bulletin for March (41: 137-208. pi. 1-6) was issued 22 Ap 1914] 


210 Harper: The "Pocosin" of Pike County, Ala. 

In Dr. Eugene A. Smith's description of Pike County in his 
report on the agricultural features of Alabama (Tenth Census 
U. S. 6: 151; Geol. Surv. Ala., Report for 1881 and 1882, p. 522. 
1884) these observations of Thornton's are briefly referred to. 
About the same time, in the 9th volume of the Tenth Census 
(p. 528), Dr. Charles Mohr published some more definite informa- 
tion about the vegetation of the same place, as follows : 

"Pike County. — On the broad ridges which form the divide between the waters 
of the Pea and Conecuh rivers, upon a purely sandy soil, are found, within the forest 
of long-leaved pine, tracts with strictly-defined outlines from a half mile to several 
miles in width, covered with a dense vegetation of small trees and shrubs peculiar to 
the perpetually moist and cool hummocks* of the coast. The soil covered with this 
growth presents no unusual features; it is as poor and arid as that covering the rest 
of these heights. Surrounded on all sides by pine forests, not a single pine tree is 
seen within the limits of these glades, called by the inhabitants 'pogosines,' an Indian 
name the meaning of which I was unable to learn. 

"The trees are of small growth, the willow oak, the water oak, beech, red maple, 
and black gum rarely rising to a height of more than 30 feet among the sourwoods, 
junipers, hornbeams, hollies, papaws, fringe trees, red bays, and other trees of the 
coast. These glades verge upon deep ravines from which issue large springs, and 
from this fact I conclude that, below their sandy, porous soil, strata must exist 
perpetually moistened by subterranean waters near enough to the surface to supply 
the moisture necessary to support such a luxuriant vegetation." 

There seems to be no reference to this interesting place in 
Dr. Smith's report on the geology of the coastal plain of Alabama 
(1895), or in Dr. Mohr's Plant Life of Alabama (1901). In the 
summer of 1906 Dr. Smith and the writer were in Pike County 
together for a short time, and heard some accounts of the "pocosin," 
which led Dr. Smith to make his first visit to it a little later. 

In 1910a soil survey of Pike County was made by W. E. Tharp, 
of the U. S. Department of Agriculture, and W. L. Lett and W. E. 
Wilkinson, representing the State; and on the map accompanying 
their report, published in December, 191 1, the location of the 
pocosin is shown, probably for the first time, but there is not a 
word about it in the text. Stranger still, its soil is not differentiated 
on the map from that of the surrounding country (" Norfolk 
coarse sand"), although it does differ in at least one important 

* Dr. Mohr doubtless wrote "hammocks," as he did in his Plant Life of Alabama 
17 years later, but it was evidently changed to "hummocks" in Washington, as it was 
throughout the 5th and 6th volumes of the same series, except on the maps, and one 
or two places in the text that escaped the proof-readers. (See Geol. Surv. Ala. 
Monog. 8: 83. 1913O 

Harper: The "Pocosin" of Pike County, Ala. 211 

Guided by the map just mentioned, the writer visited the spot 
on November 6, 1912, and March 27, 1913, and made a rough quan- 
titative study of its vegetation. An incessant rain at the time of 
the first visit interfered somewhat with note-taking and made 
photography out of the question, but conditions were more satis- 
factory the second time, when the views here published were 
taken. A brief mention of it, with the only photograph of its 
vegetation hitherto published, appeared last summer in my report 
on the forests of Alabama.* 

The so-called pocosin (Dr. Mohr's description above quoted 
implies the existence of several such areas, but I know of only one) 
embraces a hundred acres or more, mostly in Section 7, T. 9 N., 
R. 22 E., in the midst of a few square miles of undulating sandy 
country on the east side of Walnut Creek, about half way between 
Troy and Brundidge, and about 50 miles south of the fall-line 
and 100 miles from the Gulf coast. The pocosin itself is practically 
untouched by civilization, except for having one or two little-used 
roads through it, but the surrounding sandy country is partly 
under cultivation. As observed by Thornton, however, the sand 
is much less productive than the loamy soils which prevail else- 
where in Pike County and other parts of the southern red hills or 
Eocene region of the coastal plain. Where not cultivated it 
bears a vegetation much like that of the sand-hills of Georgia,! 
but the soil is evidently a little richer in mineral plant food than 
that of the average sand-hill, as shown by the prevalence of Pinus 
echinata and the scarcity of Pinus palustris.% 

In the following list of sand-hill plants growing around the 
pocosin the trees, shrubs and herbs are arranged as nearly as 
possible in order of abundance, but the data are not sufficient for 
assigning percentages to them. Evergreens are indicated by 
heavy type. 


Pinus echinata Hicoria glabra 

Crataegus Michauxii? Quercus stellata 

Quercus Catesbaei Quercus marylandica 

Quercus cinerea Nyssa sylvatica 

Quercus Margaretta Pinus palustris 

* Geol. Surv. Ala. Monog. 8: 99-100, 160-161. June, 1913. 
t See Ann. N. Y. Acad. Sci. 17: 82-89. 1906. 

% This is in a narrow belt of the coastal plain where the long-leaf pine is very rare. 
See Geol. Surv. Ala. Monog. 8: 99. 1913. 

212 Harper: The "Pocosin" of Pike County, Ala. 

Shrubs and Vines 

Batodendron arboreum Osmanthus americana 

Ceanothus americanus Chionanthus virginica 

Gaylussacia dumosa Gelsemium sempervirens 
Asimina parviflora 


Opuntia vulgaris Cracca virginiana 

Pteridium aquilinum Chrysopsis aspera? 

Afzelia pectinata Coreopsis major Oemleri 

Kuhnistera pinnata* Tillandsia usneoides 

Solidago odora Sorghastrum secundumf 

Stenophyllus ciliatifolius* Siphonychia sp. 

Polypodium polypodioides Pitcheria galactioides* 

Iris verna Astragalus villosus* 

Triplasis americana* Warea cuneifoliaj 
Ionactis linariifolius 


Cladonia sp. 

This vegetation, like that on typical sand-hills, is not very 
dense, as shown by one of the accompanying illustrations (fig. i). 
Apparently about one third of the woody plants (counting individ- 
uals, not species) are evergreen. 

The pocosin itself seems to center around the precipitous heads 
of a few small tributaries of Walnut Creek, but its vegetation, 
except in the bottoms of the ravines, is not at all of a swamp 
character, the statements of Thornton and Mohr to the contrary 
notwithstanding. Its soil was doubtless originally the same as 
that of the surrounding sandy country, but it is now covered and 
more or less mixed with a thin layer of humus, derived from the 
trees and protected from desiccation and oxidation by their shade, 
as in other dense forests the world over. In this forest there is a 
characteristic faint odor of sour humus (corresponding approxi- 
mately with the raw humus of Warming§ or more closely with the 
upland peat of Coville||), as in the mountains of North Carolina 

* These five species do not seem to have been found so far inland in Alabama 
before. Three of them are Leguminosae. 

f Apparently not previously reported from Alabama. (See Ann. N. Y. Acad. 
Sci. 17: 300. 1906.) But in September, 1912, I found it in considerable abundance 
in the pine-barrens of Clarke, Monroe and Baldwin Counties. 

% Another addition to the Alabama flora, its previously known range being from 
South Carolina to Florida. 

§ Oecology of Plants, 62-63. 1909. 

|| U. S. Dept. Agr. Bur. Plant Industry Bull. 193: 32-34. F 191 1; Jour. 
Wash. Acad. Sci. 3: 84-86. F 1913. 

Harper: The "Pocosin" of Pike County, Ala. 213 

and many other places where humus accumulates on a soil that 
is poor in animal life or not intrinsically very fertile. The bound- 
ary between the pocosin and sand-hill vegetation is not very sharp, 
but it is comparatively easy to fix it definitely enough for statis- 
tical purposes. In attempting to make a quantitative analysis 
of the vegetation, however, one encounters a difficulty in that it is 
a many-storied forest, in which there seem to be all gradations in 

Fig. i. Sand-hill vegetation near the pocosin, with Pinus echinata, Quercus 
Catesbaei, Crataegus, Batodendron, etc. 

size between large trees and shrubs, and it is not exactly right to 
include both trees and shrubs in the same list for the purpose of 
calculating percentages. The following list is divided into more 
classes than usual, and the relative position of the species within 
each class is approximately correct, but it gives no idea of the 
relative abundance of species in different classes. The illustra- 
tions, however, partly make up for this. (Figs. 3, 4.) 

Large Trees 

Quercus laurifolia 

Hicoria glabra? 
Tilia heterophylla? 
Magnolia grandiflora 
Fagus grandifolia 

Quercus alba 
Prunus serotina 
Fraxinus americana? 
Quercus velutina 

214 Harper: The "Pocosin" of Pike County, Ala. 

Small Trees 

Osmanthus americana 
Persea Borbonia 

Quercus sp.* 
Ostrya Virginiana 
Batodendron arboreum 
Cornus florida 
Viburnum rufidulum 
Prunus caroliniana 
Crataegus sp. 

Hamamelis virginiana 
Chionanthus virginica 
Sebastiana ligustrina 
Aralia spinosa 

Vitis rotundifolia 
Bignonia crucigera 

Smilax pumila 
Mitchella repens 

Trillium Hugeri 
Asarum arifolium 
Galium uniflorum 

Polygonatum biflorum 
Solidago odora (toward edges) 
Monotropa uniflora 
Panicum sp. 

Polypodium polypodioides 

Acer floridanum 

Prunus umbellata? 

Bumelia lanuginosa 

Crataegus Michauxii? (toward edges) 

Quercus Margaretta (toward edges) 

Cercis canadensis 

Oxydendron arboreum 

Ilex opaca 

Amelanchier sp. 


Callicarpa americana 
Aesculus Pavia 
Kalmia latif olia 

Woody Vines 

Rhus radicans 

Herbaceous Vines 

Dioscorea sp. 

Ordinary Herbs 

Viola sp. 
Sanicula sp. 
Dasystoma quercifolia 
Carex floridana 
Opuntia vulgaris 
Conopholis americana 


Tillandsia usneoides 

Thuidium sp. 

Bryophytes and Thallophytes 
Clavaria sp. 

It is interesting to note that among 57 species here listed as 
growing in the pocosin there is only one fern, and such large 
families as Gramineae, Cyperaceae, Leguminosae and Com- 

* An unidentified — and probably undescribed — oak, somew T hat similar in ap- 
pearance to Q. marylandica Muench. and Q. arkansana Sarg., but apparently more 
closely related to Q. nigra L. (Q. aquatica Walt.), Q. myrtifolia Willd. (as that species 
is commonly interpreted), and Q. microcarya Small. I have never seen anything like 
it elsewhere. It grows mostly toward the edges of the pocosin, but not in the sand- 
hill vegetation. It is one of the commoner species there, as indicated by its position 
in the list, and it is difficult to understand how Dr. Mohr overlooked it if he visited 
this same spot, unless he was there only in winter, when it was leafless. (Fig. 3.) 

Harper: The "Pocosin" of Pike County, Ala. 215 

positae are also represented by only one species each. There are 
five oaks (the same number as in the surrounding sand-hill area) 
three representatives of the Ericales, and three colorless sapro- 
phytes or root-parasites, namely, Monotropa, Conopholis and 

Although there are no quantitative figures to show it, just 
about half of this vegetation is evergreen. It is very similar to 

Fig. 2 

Fig. 3 

Fig. 2. Scene on sandy road just outside of the pocosin. Flowering branches of 
Quercus stellata in upper left corner; Quercus Catesbaei at right, bearing many dead 
leaves of the preceding season. 

Fig. 3. Trunk of the undescribed Quercus (34 inches in circumference, breast- 
high, and about 30 feet tall) in the pocosin near its eastern edge. 

that of some of the sandy hammocks of Georgia and Florida;* 
and it may be more or less of an accident that the name pocosin 
was applied to this place by the early settlers instead of hammock .f 

* See Ann. N. Y. Acad. Sci. 17: 98-102. 1906; Bull. Torrey Club 38: 515-517. 

t If the early immigrants had come from the southeastward instead of north- 
eastward they would doubtless have been familiar with hammocks, which are more 
prevalent nearer the coast. 

216 Harper: The "Pocosin" of Pike County, Ala. 

The proportion of evergreens is usually somewhat larger in the 
hammocks nearer the coast, however. The more remote relation- 
ships of this vegetation may be indicated by saying that it is 
intermediate in character between the deciduous forests that are 
common on rich uplands in the moderately humid parts of the 
North Temperate zone, and the " sclerophyllous forests" of 
Warming and other European ecologists. 

A list of the characteristic plants of the ravines will complete 
the description of the pocosin vegetation. They are about as 
follows (the arrangement being the same as in the two preceding 
lists) : 


Osmanthus americana 

Cornus florida 

Magnolia grandiflora 

Symplocos tinctoria 

Ilex opaca 

Hicoria alba 

Liriodendron Tulipifera 

Fagus grandifolia 

Magnolia glauca 


Kalmia latifolia 

Ilex coriacea 


Asarum arifolium 

Smilax pumila 


Thuidium sp. 

Evergreens are decidedly in the majority here. 

Previous visitors to this place have been more or less mystified 
by the occurrence of such luxuriant vegetation in such sandy soil. 
The explanation is doubtless the same as for other sandy hammocks, 
and is very simple to one familiar with conditions in South Georgia 
and Florida. 

The pocosin area, exclusive of the ravines, was presumably at 
some time in the past covered with the same sort of sand-hill 
vegetation that now partly surrounds it. Vegetation of a denser, 
more " climactic "* type must have gradually spread from the creek 
valley up the ravines to their heads, and then out across the 

* This adjective, derived from climax, is rarely if ever seen in botanical litera- 
ture, but some such word seems to be needed. Some ecologists have been using 
climatic, an entirely different word, to convey essentially the meaning here intended; 
while many use climax and mesophytic more or less interchangeably, which seems 
to be a perversion of the original meaning of the latter. 

Harper: The "Pocosin" of Pike County, Ala. 217 

sand, making more humus all the time, and crowding out the 
intolerant sand-hill plants, as in normal succession the world over; 
and it is probably still spreading slowly but surely. The pocosin 
vegetation is simply the climax for that type of soil, while the sand- 
hill vegetation is the pioneer. 

In explaining this succession there is one environmental factor 
that must not be lost sight of. Most of the plants in the pocosin, 

Fig. 4. Typical pocosin vegetation. Magnolia grandiflora (the largest trunk), 
Osmanthus, Batodendron, Prunus caroliniana, etc. Ground covered with undecayed 

as in other hammocks, are very sensitive to fire. Fire often 
sweeps through the upland pine-oak-hickory woods that are 
common on the better soils of the same region, but the sand-hill 
vegetation is ordinarily too sparse and open to carry a ground 
fire any distance, so that it protects the pocosin vegetation on 
three sides from any fires which may originate in the surrounding 
country. Protection on the remaining side is afforded by the 
swamps and bottoms of Walnut Creek, or the broken topography. 
The hammocks of the Altamaha Grit region of Georgia are similarly 
protected from fire by the creek swamp on one side of them and 
the sand-hills on the other, and this protection has been an essential 
factor in determining their present vegetation.* 

Finally this Alabama pocosin throws valuable light on the 

* See Bull. Torrey Club 38: 524-525. 191 1- 

218 Harper: The "Pocosin" of Pike County, Ala. 

relation of evergreens to soil and succession. Although a great 
deal has been written about the phenomena of succession in 
various parts of the world, no one yet seems to have published 
any satisfactory short definition of pioneer and climax vegetation 
by which they may be recognized wherever found, without knowing 
the species; and consequently every ecologist has his own views 
on these points, and perhaps no two of them agree exactly. It 
is probably pretty generally agreed that normal succession (biotic 
succession of Cowles*) involves enrichment of the soil in some 
way; and as evergreens, in temperate climates at least, are well 
known to be most abundant in the poorer soils,f I supposed until 
about two years ago that no typical climax forest could contain 
any evergreens ; and that view has found expression in my writings. 
Closely connected with that belief was one which seems to be still 
very generally held, namely, that for every (climatic) region 
there is one climax type of vegetation toward which all others are 
tending. I am now pretty well satisfied, however, that almost 
every type of soil has its own characteristic pioneer and climax 
vegetation, more or less distinct from those of other types. 

The proportion of evergreens in a given habitat or region seems 
to be correlated with the amount of available potash (and perhaps 
other minerals) in the soil,t and therefore should not be affected 
much by the sort of succession whose essential feature is the 
accumulation of humus, or the progress of nitrification. Although 
an admixture of humus is indeed believed to increase the availa- 
bility of the mineral plant foods in soil, a soil totally lacking in 
potash or lime would gain none of these ingredients from humus 
formed in place. It is even possible that in soils deficient in 
soluble minerals — as is the case with most sandy and peaty soils — 
and protected from fire like our pocosin, a considerable proportion 
of the potash within reach of the roots of trees is locked up for 
several years at a time in the dead leaves which lie on the ground 
undecayed, and thus the proportion of evergreens may actually 
increase with succession, as it does in the present case, where the 
ravines have the most evergreens and the sand-hills the fewest. 

* Bot. Gaz. 51: 171-180. 1911; Ann. Assoc. Am. Geogrs. 1: 12-19. 1912. 
f See Rep. Mich. Acad. Sci. 15: 197. 1914. 

% See Geol. Surv. Ala. Monog. 8: 28-29; Torreya 13: 140, 141, 143; Bull. 
Torrey Club 40: 398. 1913. 

Harper: The "Pocosin" of Pike County, Ala. 219 

(In the pine-barrens frequent fires return the potash, etc., quickly 
to the soil, while in calcareous or clayey soils there are usually 
many earthworms, centipedes, snails, bacteria or other soil 
organisms which assist greatly in converting the leaves into 
humus.*) Another successional factor which doubtless tends to 
diminish the availability of mineral nutrients in the soil is the 
denser shade of the climax vegetation ; for this lowers the temper- 
ature of the soil in summer and probably makes the ground- 
water level more constant, besides diminishing evaporation and 

Although no chemical analysis of the pocosin soil has been 
made, it is evident from a casual inspection that it consists mostly 
of siliceous sand, and must be rather poor in soluble minerals, 
like the sandy hammocks of Florida. The climax vegetation of the 
more clayey soils in the same region is found on river-banks, bluffs, 
and sides of ravines, where fire is kept away pretty well by the 
topography; and it differs considerably from that of the pocosin. 
The following list, of trees only, is a generalized one for the upland 
climax forests of the whole southern red hill region of Alabama. 
The species are arranged approximately in order of abundance, 
as before. 

Liquidambar Styraciflua Ostrya virginiana 

Pinus Taeda Oxydendron arboreum 

Liriodendron Tulipifera Acer floridanum 

Fagus grandifolia Fraxinus americana 

Quercus alba Tilia heterophylla? 

Cornus florida Quercus nigra 

Magnolia grandiflora Cercis canadensis 

Pinus glabra Halesia diptera 

Hicoria alba Magnolia acuminata 

Magnolia macrophylla Quercus rubra 

Ilex opaca Symplocos tinctoria 

Nyssa sylvatica Magnolia pyramidata 

Most of the species in this list are common also to the pocosin, 
but their relative abundance is different, and the proportion of 
evergreens is considerably less, being probably not over one third 
or one fourth. Evergreens naturally differ somewhat among 
themselves in their soil requirements, and it happens that the 

* Mr. Coville's valuable paper on the formation of leaf-mold (Jour. Wash. Acad. 
Sci. 3: 77-89. 1913) should be consulted in this connection. 

220 Harper: The "Pocosin" of Pike County, Ala. 

two pines here listed prefer richer soils than all the other southern 
pines and some deciduous trees. 

Although it is digressing a little from the scope of this paper, 
it is interesting to note that the hammocks and river-bluffs of the 
Altamaha Grit region of Georgia* differ from each other in much 
the same way that the pocosin does from the bluffs, etc., just 
mentioned. Both hammocks and river-bluffs are covered with 
climax forests, but the soil is sandy in one case and loamy in the 
other, which makes considerable difference in the vegetation. 
From the frequency numbers which have been published in the 
work cited, it appears that 79.6 per cent, of the trees and 30.5 
per cent, of the shrubs in the hammocks are evergreen; while the 
corresponding figures for river-bluffs are 37 and 15; a difference 
whose significance was not suspected until long after these Georgia 
lists were published. The sand-hills which border the Georgia 
hammocks and protect them from fire have been estimated in the 
same way to have 28.2 per cent, of their trees and 48.3 per cent, 
of their shrubs evergreen. 


This so-called pocosin (which has little in common with the 
typical pocosins of North Carolina) is a many-storied climax forest 
of a type characteristic of dry sandy soils in the coastal plain of 
Alabama, Georgia, and northern Florida. The accumulation of 
humus — and consequently the development of climax vegetation — 
began in ravines, and has been favored by the protection from fire 
afforded by the sparseness of the surrounding pioneer vegetation. 

Something like half of the woody plants of the pocosin are 
evergreen, which is evidently a larger proportion of evergreens 
than in the case of the pioneer vegetation of the same soil and of 
the climax vegetation of soils richer in mineral plant food in the 
same region and elsewhere. 

Each fundamentally different type of soil seems to have its 
own characteristic pioneer and climax vegetation; and the pro- 
portion of evergreens in this case — if not in many others — increases 
with normal succession, owing probably to the lowering of soil 
temperatures during the growing season, and to the locking up of 
plant food in undecayed leaves or sour humus, among other 

♦Ann. N. Y. Acad. Sci. 17: 98-109. 1906.