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OHIO STATE ACADEMY of SCIENCE,

Volume IV, Part 4.

oe ee Special Papers No. 10.

een STUDY

Af. BRUSH LAKE

John H. Schaffner
Otto E. Jonuaids
Frederick J. Tyler

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- COLUMBUS, OHIO,
1904.

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PROCEEDINGS

OF THE

Ohio State Academy of Science.

Vol. IV, Part 4.

Ecological Study of Brush Lake,

BY

JOHN H. SCHAFFNER, OTTO E. JENNINGS and
PREDRICK A. DYVEER,

SPECIAL PAPERS, No. 10.

PUBLICATION COMMITTEE:
JOHN H. SCHAFFNER, JAMES S. HINE, GERARD FOWKE.

Columbus, Ohio, December 1, 1904.

COLUMBUS, OHIO:
SPAHR & GLENN, PRINTERS.
1904.

The work on which the following paper is based was carried
on with the aid of several small grants from the Emerson
McMillin Research Fund, and the expense of publication is met
by a further grant from the same fund.

WILLIAM R. LAZENBY,

F. M. WEBSTER,

JoHN H. SCHAFFNER,
Trustees.

INTRODUCTION.

INCE a considerable part of the State of Ohio was once
covered by the continental glacier of the glacial epoch, the
present surface is in many places covered by a thick
deposit of drift. In the regions of terminal moraines and

moraines of recession, the surface is usually diversified by hills
and hollows with a comparatively new and irregular drainage
system. ‘The depressions thus formed give rise to the numerous
swamps, ponds and lakelets, which constitute a very character-
istic feature of the landscape and have a very important bearing
on the plant distribution.

Being interested in the plant geography and ecology of the
State, the authors proceeded to make a systematic study of one
of these glacial lakelets. Brush Lake being favorably situated
was chosen for study and the work of observation and collecting
has been carried on for several years. ‘To help defray necessary
expenses, several small grants were obtained form the McMillin
Fund of the Ohio State Academy of Science and we wish here to
express our thanks to the Academy for the assistance received.
Thanks are also due to Mr. C. F. Wheeler, of the United States
Department of Agriculture, for kindly determining the species of
Cyperaceae, and to Mr. Geo. Riddle, owner of the lake, for the
photograph of the lake taken in 1887.

Ecological Study of Brush Lake.

GENERAL DESCRIPTION OF THE LAKE.

RUSH LAKE is situated in the north-east corner of
Champaign County, on the north side of the “‘ Pan-
handle’’ Railway, at Brush Lake Station, about thirty-
five miles west of Columbus. It is a pond covering

about eleven acres, occupying a depression of the glacial deposit
which covers the entire region for miles around. This deposit
represents a moraine of recession and the surface is diversified by
hills and hollows, the district being one of the most beautiful in
central Ohio. In the neighborhood there are numerous small
swamps and ponds, some of which have been entirely filled up
with sediment from the surrounding banks and hills. It is said
that Brush Lake was formerly about eighty feet deep. If this is
true there has been a large amount of filling in recent times from
the adjoining cultivated hillsides ; for at present the water is not
over thirty-five feet deep in the deepest place. The elevation of
the surface of the lake is given as 1,120 feet above sea level.

There is a small ravine opening into the lake at the north-
west and an outlet at the south-east from which water usually
flows, forming a small brook, except in very dry weather when
the loss from evaporation and other causes is greater than the
supply. The outlet seems to be eroded very slowly and the
decrease in the size of the lake due to this cause is at present
insignificant. The water supply comes from a small drainage
area and from springs which are evident on the west and north-
west sides. From wells drilled at Fountain Park, about one mile
south-east of the lake, it appears that the underlying rock is the
Cedarville Limestone, belonging to the Niagara formation. There
are several shallow artesian wells from this limestone at Fountain
Park, but whether any of this rock water comes up into Brush
Lake is not known.

152 OHIO STATE ACADEMY OF SCIENCE.

Around the margin of the lake is a fringe of trees, the rem-
nants of the former general forest, and within this is a series of
concentric zones of vegetation which finally disappear in the
water, as is usual in such locations. Evidence of rapid filling is
present on the west side, where a new series of zones has pro-
duced considerable confusion in the centripetal progression. On
the east side there is a wide mud flat inside of the shrub zone,
which is just now beginning to be invaded by hydrophtic shrubs.
The most perfect and primitive arrangement of the vegetation
appears at the north end, where a small, low wood-lot has afforded
protection from the cultivated field beyond. At the south end
the natural conditions have been entirely changed; here the
vegetation has been removed in order to enlarge the available
ice-producing surface. The water is thus shallow and some of
the zones are either entirely absent or represented only by isolated
individuals. There is here also a patch of low woods which lies
between the railroad and the lake and formerly the zones were
very pérfectly developed, as will appear from the photograph
takemune 1837) (hig. 1).

Glacial lakes are of interest in many ways, but especially
because of the rapid changes which must have taken place in
comparatively recent times in climate and soil. How far these
lakes present similar plant societies as one passes from their
southern limits northward is still to be determined. Several
glacial lakes have recently been studied in detail, among which
may be specially mentioned the ‘‘ Three Sister Lakes,’ near
Ann Arbor, Mich.’

One of the authors of the present paper is quite familiar with
the vegetation and surroundings of these ‘‘ Three Sister Lakes,’’
having often botanized on their banks, and though there are
striking similarities in some of the zones, on the whole there are
very great differences, as will appear by comparing the reports of
Reed and Weld with the description of Brush Lake. That the
difference is not primarily due to latitude will be evident from the
fact that a number of plants characteristic of the Michigan lake-
lets also occur in the Licking Reservoir, about thirty miles east

I. REED, HOWARD S. A Survey of the Huron River Valley. I. The Ecology of
a Glacial Lake. Bot. Gaz. 34: 125-139. 1902
WELD, Lewis H. Botanical Survey of the Huron River Valley. II. A Peat
Bog and Morainal Lake. Bot. Gaz. 37: 36-52. 1904.

ECOLOGICAL STUDY OF BRUSH LAKE. 153

of Columbus. Probably the most important factor is the presence
of Sphagnum, which is abundant in some parts of the Licking
Reservoir. But why the Sphagnum should be abundant in the
reservoir and entirely absent in Brush Lake is not so apparent.
The general character and surroundings of Brush Lake are much
the same as those of the ‘‘ Three Sisters.’’

For the present the writers will content themselves with a
report of the conditions as found at Brush Lake, leaving gener-
alizations to some future ecologist. No special work could be
carried on in regard to physiological adaptations. In order to do
such work it is necessary that one should be able to “ve with his
plants for a considerable period of time. But ecological phyto-
geography is still in its embryonic stage and it is perhaps better
for the present to continue work more along geographical lines
until better facilities are at hand for accurate and continuous
observations on physiological adaptations. Besides, our present
plant societies are being destroyed so rapidly that it is of primary
importance that an historical record should be made. ‘This may
be of the utmost importance in the future.

THE PLANT SOCIETIES.

As stated above, the plant societies of the lake are arranged
in concentric zones, as is usual where there is a gradual change
in the environment. The zones determined are as follows:

Submerged Zone.
Water-lily Zone.
Half-submerged Zone.
Decodon Zone.
Uliginous Zone.
Shrub Zone.

Forest Zone.

AnBwWN H

NI

Of these, all may be regarded as normal except the uliginous
zone, which to a large extent represents a recent society developed
on the mud flats intercalated between the Decodon and shrub
zones on the east and west sides of the lake.

I. SUBMERGED ZONE. In this zone existence is almost
entirely under water, for rarely do any of the plants composing
it have even their tips extending above the surface. It is essen-
tially a Potamogeton-Ceratophyllum-Myriophyllum-Chara zone.

154 OHIO STATE ACADEMY OF SCIENCE.

It extends in typical places from a depth of 5 feet on the outer
side, where it is bounded by water-lilies, to a depth of 10 feet or
more on the inner side. At the north end where conditions are
ideal the zone is 15 feet wide between the 5 and 1o-feet limits.
On the west side it is 20 feet between these limits. Beyond the
to-feet limit the depth increases very rapidly. The water of the
lake is considerably colored, which must have an important effect
on the submerged vegetation. All the plants in this zone have
slender, wand-like stems with narrow and slender or much dis-
sected leaves or branches. ‘They are all highly specialized and
thoroughly adapted to their habitat. They appear to occupy the
ground because no other plants are able to follow. On the outer
side they are pushed back by the water-lilies as far as these are
able to invade the water. The typical plants are :

Potamogeton zosteraefolius Schum.

es lucens L.

Ceratophyllum demersum L,.

Myriophyllum sp.

Chara sp.

Other species are :

Potamogeton foliosus Raf.

ui pectinatus L,.
Naias flexilis (Willd.) R. & S.
Zannichellia palustris L.

On the surface are frequently found the free-floating duck-
weeds :

Spirodela polyrhiza (L,.) Schl.
Lemna minor JL.
Wolffia columbiana Karst.

2. WATER-LILY ZONE. This isa Nymphaea-Castalia zone,
the two plants that give character to the society being Nymphaea
advena Soland. and Castalia odorata (Dryand) W. & W. It is
said that the Castalia was introduced artificially, but it is now
well established. At the north end the zone is 4o feet wide and
extends from water five feet deep to two feet deep. On the west
side it is 28 feet wide. This is a very striking zune on account
of the large, upright leaves of Nymphaea. ‘The comparative
absence of Nymphaea in water shallower than two feet must be
accounted for on the grounds of a severe struggle with the plants

ECOLOGICAL STUDY OF BRUSH LAKE, 155

of the next zone, since it will grow readily in much shallower
water. The inner limit of the zone appears to be determined by
the depth of water alone, the plants being able to advance readily
so long as the petioles are able to elongate sufficiently to bring
the leaf blades above the surface. On the west side there are
several small gaps, probably because of the recent origin of the
present zone on this side and these gaps are filled with great
masses of Chara. Another prominent plant of this zone is
Potamogeton natans L,., which in several places covers considera-
ble areas.

The water-lilies occupying the shallow water are very efficient
agents in building up the shore of the lake. The stout rhizomes
are able to creep inward and bind the loose soil together, while
the petioles and leaves tend to produce a calm where debris may
accumulate quite rapidly.

Among the floating and aerial leaves of the water-lilies and
other plants are usually great swarms of duckweeds, especially
Spirodela polyrhiza (.) Schl., Lemna minor L., and Wolffia
columbiana Karst. Riccia fluitans L,. is also common. Riccio-
carpus natans (1,.) Corda., although occurring in large quantities
in the swamps near by, was not collected in the lake. Batrachium
divaricatum (Schr.) Wimm. is abundant in some places at the
outer edge of the water-lilies, but Ranunculus delphinifolius
Torr, common in the swamps and ponds of the region, was not
present.

Other plants collected in the water-lily zone were :

Sparganium eurycarpum Engel.
Potamogeton foliosus Raf.

ae pectinatus L.

ee lucens L.
Naias flexilis (Willd.) R. & S.
Zannichellia palustris L,.
Ceratophyllum demersum IL).
Myriophyllum sp.

3. HALF-SUBMERGED ZONE. This is essentially a Rumex-
Polygonum-Typha zone. It is characterized by plants which’
have their roots, rhizomes, and the lower parts of their erect
stems under water, but the larger part of the erect stems is
exposed to aerial conditions. It is much more complex and vari-
able than the two preceding zones. It extends outwards from

156 OHIO STATE ACADEMY OF SCIENCE.

the edge of the water-lily zone at a depth of two feet to water
about one-half foot deep. At the north end it is twenty-four feet
wide and on the west side about fifteen feet. It is most perfectly
developed at the north end (Fig. 2), where Rumex verticillatus
L., Polygonum amphibium JL. and Polygonum emersum (Mx. )

Fig. 2. North end of the Lake, showing plant zones. ‘The Half-sub-

merged Zone and Decodon Zone are not well marked in the picture be-

‘ pte of the undeveloped condition of the latter. (Photograph taken June
78, 1902.)

Britt. are the characteristic species. On the east and west sides,
owing to more typical uliginous conditions, Typha latifolia L.
and Sparganium eurycarpum become prominent. On the south

ECOLOGICAL STUDY OF BRUSH LAKE. 157

side the wide, shallow, artificial area of water corresponding to
this zone is mostly covered with Chara sp., various pond weeds,
Batrachium divaricatum (Schr.) Wimm., and Zannichellia
palustris L,.

An interesting plant also is Cicuta bulbifera L., which is
covered in the fall with little bulbs. These drop off and float
around on the surface of the water. Although found in several
places this plant does not seem able to hold much ground consid-
ering the great advantage it has of being distributed into every
favorable nook and corner by means of its brood buds. Eleocharis
palustris (L.) R. & S. and Scirpus lacustris L. are also promi-
nent in this zone. The floating plants of the water-lily zone are
abundant, as would be expected. Other plants which are present
are as follows:

Roripa palustris (I,.) Bess.
Naumbergia thyrsiflora (1,.) Duby.
Scutellaria lateriflora L.

Bidens cernua L.

Polygonum punctatum E11.

Alisma plantago L.

Sagittaria latifolia Willd.

4. DECODON ZONE. This is one of the most remarkable
societies surrounding the lake. It isa Decodon-Solanum dul-
camara zone. The characteristic plant, which in many plac.s
forms almost a pure society, is the tall crownformer, Decodon
verticillatus (L.) Ell. The twining bittersweet, Solanum dul-
camara L,., is also very prominent. Some of these plants develop
as floating individuals, having no connection with the ground,
but developing numerous water roots along the submerged part
of the stem. This zone is 30 feet wide at the north end. It
begins in water from one to one-half foot deep and ends at the
outer edge in water of about three or four inches, or even beyond
the water’s edge. At the north end it is limited on the outside
by the shrub zone which extends to the edge of the water or
beyond. The tali shoots of the Decodon, many of which are
fasciated, form a tangled mass through which it is very difficult
to pass both when they are green and in winter when dry. The
Decodon is especially well adapted for holding air in the cortical
layer of the much branded base and is thus well fitted to carry on

158 OHIO STATE ACADEMY OF SCIENCE.

the life of an aquatic crown-former. The Decodon zone is almost
entirely wanting at the south end of the lake, having been
recently destroyed as stated before. It was very perfect here
formerly, as appears in Fig. 1, and at the south-east it is still
very wide. On the west side the zone is rather narrow, being
only abont fifteen feet wide. :

Other plants in this zone are:

Alisma plantago L. Ranunculus abortivus L,
Sagittaria latifolia Willd Roripa hispida (Desv.) Britt.
Scirpus lacustris L. Naumbergia thyrsiflora (1,.) Duby.
Carex comosa Boott. Cicuta bulbifera L,.

Iris versicolor L,. Cephalanthus occidentalis L.

The Cephalanthus is here and there an invader from the out-
side and will finally establish a new shrub zone because of the
changed conditions produced by cultivation of the surrounding
hillsides. Had the lake remained in its natural condition sur-
rounded by dense forest the progress of the zones would probably
have been gradual and continuous, but as it is there will be from
time to time comparatively sudden advances, thus producing con-
fusion in the established order of the old societies.

Unicinous ZONE. The distinctive peculiarity of this zone
is the presence of various species of Carex, Eleocharis and Scirpus,
together with Equisetum fluviatile L., which is very abundant in
some places. Besides these there are a number of other moisture
and mud-loving species. ‘This zone is intercalated on the east
and west sides where wide mud flats have been formed between
the Decodon and shrub zones. It is very prominent on the east
side where there has been much filling in from the cultivated
field beyond. The zone is absent at the north where there has
been no such filling and was probably also absent from the south
end when natural conditions still prevailed. In the moister parts
the Equisetum, Eleocharis and Scirpus are characteristic, while
in the outer, dryer margin the various species of Carex form a
thick sod in which occur a number of uliginous herbs. Some
isolated pioneers among the shrubs, especially Cephalanthus,
have also taken a foothold on the east side although still few
in numbers. On the west side the zone has been much invaded
and is now in a transition state, progressing rapidly toward
a thicket and forest society.

ECOLOGICAL STUDY OF BRUSH LAKE. 159

The plants in the zone are as follows:

HOMOSPOROUS PTERIDOPHYTES.

Equisetum fluviatile L. Dryopteris thelypteris (1,.) Gr,
SEDGES.
Cyperus strigosus L. Carex frankii Kunth.
Eleocharis palustris (L.) R. & S. ‘« -granularis Mubl.
“ palustris glaucescens ‘© hystricina Muhl.
[( Willd.) Gr. “« lanuginosa Mx.
G6 acicularis (l.) R. & S. ‘““ shortiana Dew.
Scirpus fluviatilis (Torr.) Gr. ‘« stipata Muhl.
** atrovirens Muhl. ** stricta Law.
<< lineatus Mx. ‘* straminea ferruginea Bail.
Carex albolutescens Schwein. (?). [(C. alata ferruginea Fern.)
‘© comosa Boott. ‘ yulpinoidea Mx.

«¢ eristatella Britt.
GRASSES.

Echinochloa crus-galli (1,.) Beauv. Panicularia nervata (Willd.) Ktz.
Panicum capillare L.

OTHER MONOCOTYLS.

Sparganium eurycarpum Engel. Juncus tenuis Wild.
Spathyema foetida (L.) Raf. PCOLLein Cave

HERBACEOUS DICOTYLS.

Batrachium divaricatum (Schr. ) Mentha canadensis L.
[Wimm. Mimulus ringens L.
Caltha palustris L. Pedicularis lanceolata Mx.
Cardamine bulbosa (Schreb.) B.S. P. Angelica atropurpurea L.
as pennsylvanica Muhl. Galium claytoni Mx.
Roripa palustris (1,.) Bess. << timctorimm) 1:
Penthorum sedoides L. ‘« asprellum Mx.
Geum virginianum L,. Valerianella radiata (1,.) Dufr.
Naumbergia thyrsiflora (1,.) Duby. Lobelia syphilitica L.
Asclepias incarnata L, Aster puniceus L.
Lycopus americana Muhl. Senecio aureus L.
SHRUBS.

Cephalanthus occidentalis L.

6. SHRUB ZONE. This is a Salix-Cephalanthus-Cornus-
Rosa zone. It is almost continuous around the lake except at
the south side where it is poorly developed, forming only a nar-
row, interrupted belt between the forest and water. At the
north end the zone is 30 feet wide. Here abound some of our

160 OHIO STATE ACADEMY OF SCIBNCE.

typical moisture-loving shrubs, forming at some places an almost
impassable hedge. At the north-west where the small ditch
opens into the lake the shrubs have invaded the water, Salix
sericea Marsh. and S. lucida Muhl. advancing farthest.

The most characteristic plants are a number of species of
Salix, Cephalanthus occidentalis L., Cornus stolonifera Mx. and
Rosa carolina IL. The complete list of shrubs found numbers
fifteen species and two forms, as follows :

Salix discolor Muhl. Rosa carolina L,
“sericea Marsh. Solanum dulcamara 1.
“* cordata Muhl. Cornus stolonifera Mx.
““ cordata augustata (Pursh.) And. “ amomum Mill.
‘* sericea x cordata. Cephalanthus occidentalis L.
“lucida Muhl, Viburnum opulus L,
“« nigra Marsh. oi lentago L.
‘“ amygdaloides And. Sambucus canadensis L.

Ribes cynosbati L,.

Several of these develop into large trees, but none had
advanced beyond the shrub stage, either on account of age or
other causes. Because of the great density of the shrub thicket
very few herbs gain a footing in this zone except in the more
open places. The following sixteen species were collected :

Spathyema foetida (1.) Raf. Naumbergia thyrsiflora (1).) Duby.
Polygonum persicaria L. Asclepias incarnata L,.

Caltha palustris L. Blephilia hirsuta (Ph.) Torr.
Ranunculus abortivus L. Mentha canadensis L.

Geum canadense Jacq. Monarda fistulosa L.

Cassia marylandica L. Veronica peregrina L.

Lathyrus palustris L. Campanula americana L,.

Viola obliqua Hill. Rudbeckia speciosa Wend.

7. ForEST ZONE. ‘The inner part of the forest zone is
hydrophytic or semi-hydrophytic. It is typically an Acer-Ulmus-
Fraxinus-Salix zone. The soil is largely made up of vegetable
and shell humus, in which, besides the tree growth, are found
large numbers of semi-hydrophytic and mesophytic shrubs and
herbs. On the east and west sides there is only a narrow fringe
of forest left, the hillsides having been entirely denuded of their
former mesophytic forest. On the north and south ends there
are still rather wide strips of hydrophytic forest, but beyond these
the forests have also been destroyed so that it is impossible at

ECOLOGICAL STUDY OF BRUSH LAKE. 161

present to obtain the transition from the lake shore forest to the
culmination forest of the region. For this reason the normal
upland forest will not be considered here. ‘The typical trees are :

Acer saccharinum L,. Salix nigra Marsh.
Fraxinus americana L,. ‘« amygdaloides And.
ss pennsylvanica Marsh. ‘© discolor Muhl.

Ulmus americana L,.
All of these are reproducing well and advancing inward upon
the shrub zone.

In the drier, outer parts of the forest zone are also found the
following trees :

Gleditsia triacanthos L. Prunus americana Marsh.
Populus deltoides Marsh. Cornus florida L.

Morus rubra L,. Rhus glabra L,.
Viburnum prunifolium L,. Juglans nigra L.
Viburnum lentago L. Quercus macrocarpa Mx.

There are comparatively few shrubs in the typical swamp
forest. The following were collected :
Cornus amomum Mill. Opulaster opulifolius (1,.) Ktz.

Sambucus canadensis L. Rubus occidentalis Ly.
Viburnum opulus L.

In the drier parts the three lianas given below are quite
abundant :

Rhus radicans L.
Parthenocissus quinquefolia (I,.) Planch.
Vitis vulpina L.

In the outer, drier portions of the forest zone herbs are quite
numerous. ‘This is probably due to the changed and still chang-
ing conditions, as a considerable number would probably be
absent if conditions were normal as formerly, when the hydro-
phytic forest was continuous with the vast mesophytic forest of
the region. Probably most of the herbs present were collected,
and the following is the complete list of species, none of which is
especially prominent over others in the society :

Equisetum arvense LL, Cinna arundinacea L,
Arisaema triphyllum (L,.) Torr. Poa pratensis L.
Spathyema foetida (1,.) Raf. Elymus striatus Willd.

ce

Panicum capillare L. virginicus L.
Muhlenbergia mexicana (L.) Trin. ss canadensis L.

162

Cyperus diandrus Torr.
Carex comosa Boott.

“ frankii Kunth.

‘« grisea Wabl.

«« stipata Muhl.

“« —eristatella Britt.

Allium canadense 1.

Iris versicolor L.

Sisyrinchium graminoides Bickn.
Urtica gracilis Ait.

Adicea pumila (1,.) Raf.
Boehmeria cylindrica (1,.) Willd.
Parietaria pennsylvanica Muhl.
Rumex altissimus Wood.
Polygonum lapathifolium L.

s punctatum Ell.
Phytolacea decandra L,.
Claytonia virginica L.

Alsine media I.
Syndesmon thalictroides (1,.) Hoff.
Ranunculus abortivus L,.

s recurvatus Poir.

ms hispidus Mx.
Thalictrum dioicum IL.

io purpurascens L,
Caulophyllum thalictroides (1.) Mx.
Podophyllum peltatum L.
Sanguinaria canadensis I.
Barbarea barbarea (1,.) MacM.
Roripa palustris (I..) Bess.
Cardamine purpurea (Torr.) Britt.
Bursa bursa pastoris (1,.) Britt.
Camelina sativa (L,.) Crantz.
Arabis hirsuta (L.) Scop.

** laevigata (Muhl.) Poir.
Fragaria virginiana Duches.
Potentilla monspeliensis L.

a canadensis LL.

Geum canadense Jacq.

‘- -virginianum I).

Cassia marylandica Ly.

Lathyrus palustris L.

Oxalis grandis Small.
eaolacea ly:

Euphorbia corollata L.

Impatiens biflora Walt.

Hypericum maculatum Walt.

as mutilum L,
Viola papilionacea Ph.

‘* pubescens Ait.

Samolus floribundus H. B. R.
Asclepias incarnata L,.
Cuscuta gronoyil Willd.
Phlox divaricata L.
Verbena urticifolia L.

or hastata L.

OHIO STATE ACADEMY OF SCIENCE.

Scutellaria lateriflora I.
Glecoma hederacea I).
Prunella vulgaris L,.

Monarda fistulosa J).

Blephilia hirsuta (Ph.) Torr.
Koellia virginiana (1).) MacM.
Mentha canadensis IL.
Solanum carolinense L,.

i dulcamara Ly.
Verbascum thapsus I,.
Scrophularia marylandica L.
Chelone glabra Ly.

Veronica officinalis L.

of serpyllifolia L.

S peregrina L,.

eB arvensis L,.
Afzelia macrophylla (Nutt.) Ktz.
Ruellia ciliosa Ph.
Plantago lanceolata L,.

es major L,.
Sanicula gregaria Bick.
of canadensis Ly.

oan trifoliata Bick.
Washingtonia claytoni (Mx.) Britt.
Thaspium barbinode (Mx.) Nutt.
Pastinaca sativa L,.
Galium aparine L.

Be tinctorium I,.

* claytoni Mx.

“ asprellum Mx.
Valerianella radiata (I,.) Dufr.
Campanula americana L.

Lobelia cardinalis L.

«< syphilitica L.
Ambrosia trifida Ly.
Vernonia maxima Sm.
Eupatorium maculatum L.

fs perfoliatum L.
a ageratoides LL. f.
Solidago canadensis L.
Aster novae-angliae L,.

‘© puniceus L,.

“« tradescanti L.
Erigeron philadelphicus L.

us annuus (1,.) Pers.
Polymnia canadensis L.
Heliopsis scabra Duval.
Rudbeckia triloba L,.
rf speciosa Wend.
Bidens, cernua LL.

= connata Muhl.

SH trichosperma (Mx.) Britt.
Carduus discolor (Muhl.) Nutt.

os muticus (Mx.) Pers.
Taraxacum taraxacum (1,.) Karst.
Lactuca canadensis L.

ECOLOGICAL STUDY OF BRUSH LAKE. 163

GENERAL CONSIDERATIONS.

That the plants around the lake are arranged in rather defin-
ite zones appears to be due to two general causes: first, because
of the gradual change in the character of the substratum and
other factors from one condition to another; second, because
certain plants are especially adapted to certain conditions and are
thus able to hold their ground against invaiders from the outside.
In an ordinary pond the successive modifications of the sub-
stratum occur in concentric belts and hence the succession of
more or less perfect zones or belts of vegetation. Between each
two contiguous zones there is a tension line where the struggle
for existence among the opposing individuals becomes very
severe. Each zone, therefore, has a fighting line on its inner
and outer edge, while in the central part the struggle is only
between plants of the community, both old and young, and such
chance strangers which may be able to gain a foothold in the less
densely populated areas. That many plants almost entirely,
restricted to a single zone can hold their own, either farther in
or out, if once established is readily seen where normal conditions
have been disturbed. ‘There may thus be considerable difference
in the result, depending on whether plants have had the oppor-
tunity of occupying a bare soil or whether they must contend for
the soil already occupied by others. Certain species might hold
their own indefinitely in a certain environment 1f once firmly
established, while they might not be able to gain a foothold if
the soil is already occupied by others.

The seven zones of Brush Lake are slowly traveling inward,
as the lake is filling up with the wash from the surrounding hills.
Each zone follows up its ideal environment and is crowded out
on the outer margin by its next neighbor. ‘The filling must have
been quite slow and gradual in former times, but at present it is
rather cataclysmic and will continue to be so inthe future. There
are therefore unusual disturbances in the progression of the zonal
societies which have been alluded to above. The physiographic
changes determine the changesin the zones. If these are gradual
and slow in their progression the same will be true of the plant
societies, but if the filling is sudden and large additions are made

164 OHIO STATE ACADEMY OF SCIENCE.

to the lake shore, in a comparatively short time the societies
become disturbed and may make sudden advances without defin-
itely occupying the intervening ground.

The final result of the filling of the lake and the progression
of the zonal societies will be a moist mesophytic forest. Near
Brush Lake there are many small swamps and ponds, in various
stages of destruction, which show quite strikingly what the
actual history with any given set of conditions willbe. If the
filling is slow and uniform, the final stage before the hydrophytic
forest is a swamp, shrub society. In these swamps the same
shrubs mentioned above as occurring in the shrub zone of Brush
Lake are the predominant vegetation. Cephalanthus, various
willows, dogwoods, and swamp roses take possession and these
are followed by the silver maple, white elm, white and red ash,
black and peach-leaf willow, and other trees.

There is an interesting extinct or nearly extinct pond about
three-fourths of a mile north of Brush Lake on rather high
ground in a small, unpastured forest. A ploughed field extends
near one side which has evidently been responsible for some rapid
filling in recent years. ‘The fringe of hydrophytic shrubs is still
near the margin and just outside of this is a young and very
thick zone of white ash. ‘The whole centre inside of the shrub
zone is an open, flat, nearly circular area with a small depression
in the centre about ten feet across. During dry seasons the water
disappears entirely and the area is covered with rank moisture-
loving weeds, while in a wet season it is covered with water sev-
eral feet deep.

In the fall of 1902, Nymphaea advena Sol. was present in
the small depression in the centre, although the leaves were
mostly dry. No pond lilies were evident outside of this depres-
sion, although the area was carefully searched. Along with the
Nymphaea and around it was an abundance of Polygonum
punctatum Ell., and surrounding this was a dense growth of
Polygonum hydropiperoides Mx. The last mentioned plant
extended outward to the shrub zone. But at some distance from
the centre the Polygonum was intersperced with very tall plants
of Erechtites hieracifolia (L.) Raf. and other moist ground
weeds as—

ECOLOGICAL STUDY OF BRUSH LAKE. 165

Echinochloa crus-galli (1.) Beauv. Solanum nigrum L,

Panicum capillare L. Ambrosia artemisiaefolia L.
Polygonum pennsylvanicum L,. Leptilon canadense (L,.) Britt.
Phytolacca decandra L. Carduus lanceolatus L.

The Phytolacca did not extend very far beyond the shrub
zone. In and outside of the shrub zone, which was composed
mainly of Cephalanthus, willows, dogwood and rose, there was
an abundance of sedges belonging mainly to the species—

Carex lupulina Muhl. Carex muskingumensis Schw.
‘« squarrosa L. F

As stated above, in and about this sedge society and extend-
ing down to the narrow shrub zone there is a remarkable zone of
young saplings and seedlings of Fraxinus americana L., forming
almost a continuous circle around the shallow bank of the filled
pond. ‘These trees have probably developed within recent years
since the pond has practically become extinct. The forest zone
just outside of the sapling zone is rather dry and mesophytic and
consists of elms, ashes, cottonwoods, oaks, hickories, hackberries,
dogwoods, etc.

In the spring of 1903 there was a partial reversion to former
conditions. A long period of abundant rains had filled the dry
basin, flooding even the shrub zone; and the surface of the pond
was diversified by an abundance of the green leaves of Nymphaea
advena Sol. One visiting this spot for the first time would never
have dreamed of the moist-ground weed society which had cov-
ered the place eight months before. With the return of the
water the pond lillies revived, although had the dry season con-
tinued for a year longer they would probably have mostly
perished.

In this pond there will be an oscillation between hydrophyte
and mesophyte societies for many years to come. But finally the
last pond lily will disappear, having struggled not only against
living enemies, but against the inevitable change in the physio-
graphic conditions. The surface of the pond will then be rapidly
covered by a mesophytic forest, if man does not overrule the
orderly process of nature. At some distant day Brush Lake will
be in the same condition as the dying pond and only the spade or
drill will reveal the former existence of the present basin with its
hydrophytic flora.

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