Geobotany
(All information referenced and quoted from Linking Geology and Botany … a new approach, by Jane L. Forsyth (Fall 1971)).
To broadly summarize or separate the geology of Ohio into two parts, there is the western part that is “underlain” with limestone (which is a type of rock that is relatively non-resistant in Ohio) that, as a result of hundreds of millions of years of erosion, has led to the flat landscape that is now present. On the other hand, the eastern landscape of Ohio is “underlain” largely by sandstone, which compared to limestone, is a very resistant rock that is not as easily eroded. Although sandstone readily allows the flow of water throughout, the erosion process of this type of rock takes a very long time, thus giving it this “resistant” characteristic, and physical characteristics of the land that are the complete opposite of the flatlands in the western regions of Ohio.
The original sequence of sedimentary rock strata were “a thick series of limestone layers overlain by shales which were in turn overlain by sandstones.” As a result of the tilting of this original sequence of sedimentary rock strata, an arch was formed around 200 million years ago, prior to the process of erosion. This arch has experienced erosion that has exposed “the oldest rocks along its crest,” which is located in western Ohio (representing where the arch stood the highest) and runs north-to-south throughout the state. In contrast, the low-lying foot of this arch is located in the eastern region of the state, which represents the “youngest rock layers.” Finally, the important “preglacial” river system that occupied Ohio for a very, very long time was called the Teays River. This river flowed for nearly 200 million years, which across this vast span of time, worked to erode the land that it flowed throughout. The activities of this river were only curtailed by the advance of the glaciers of the Pleistocene Epoch.
During the invasion of the Pleistocene glaciers in Ohio (which was only a few hundred thousand years ago), there was a landscape feature that slowed the glaciers which has lead to the very obvious glacial boundary that cuts across the state. This feature was the “steep-sided sandstone hills of eastern Ohio,” leading to the aforementioned glacial boundary that “is no further south than the latitude of Canton.” On the western side of the state, this landscape feature was not present and allowed the glaciers to advance further south (as far as northern Kentucky).
Glacial till can be described as “an unsorted mixture of sand, silt, clay, and boulders”. In terms of its general composition, these materials were directly accumulated and deposited by “glacial meltwater.” Imagine the incredible amount of materials that are being lifted and deposited from the landscape throughout the advance of these glaciers! This glacial till can be seen as a “continuous blanket over almost all of glaciated Ohio.” Further, the glacial till in Ohio differs significantly in the eastern and western regions of the state, based almost solely on the given geological materials that are present. For example, in western Ohio, the glacial till is “rich in lime and clay,” which is a direct result of the movement of glaciers across the limestone rich landscapes of this region. To the east, however, there is very little lime and clay present within the glacial till. Predominantly comprised of sand and gravel deposits, eastern glacial till represents “mostly materials washed out beyond the glacial margin.”
The basic substrate for plants in western Ohio aligns directly with the underlying geology, being that common substrates in this area are “limy, clayey till” which offers a generally “impermeable soil,” that in terms of drainage, aeration, and pH, offers poor drainage, inadequate aeration, and a high pH level for more limy soils (with low levels of acidity) with comparably high levels of nutrient availability. In eastern Ohio, the “very permeable sandstone bedrock” provides a highly acidic substrate that is low in nutrient availability, which is “especially dry on the tops of the hills.” The acidity and structure of the substrates in eastern Ohio provide a “supply of moisture that is continually both available and cool because it comes from springs,” which is water that has been sieved through the sandstone (which again, is permeable) and then is released “deep in the valleys without being sunwarmed.” Directly from the writing by Forsyth, “where the sandstone is mantled by till, the amounts of clay and lime in the till result in less acid, more moist, and more nutrient-rich soils.”
Five species of trees/shrubs that have a distribution generally limited to the limestone or limey substrates are: redbud (Cercis canadensis), blue ash (Fraxinus quadrangulata), chinquapin oak (Quercus muehlenbergii), sedge (Carex eburnea), and snow trillium (Trillium nivale).
Five species of trees/shrubs that have a distribution generally limited to high-lime, clay-rich substrates developed in the thick glacial till of western Ohio are: sugar maple (Acer saccharum), beech (Fagus grandifolia), shagbark hickory (Carya ovata), white oak (Quercus alba), and the white ash (Fraxinus americana).
Five species of trees/shrubs that have a distribution generally limited to the sandstone hills of eastern Ohio are: chestnut oak (Quercus montana), sourwood (Oxydendrum arboreum), hemlock (Tsuga canadensis), pitch pine (Pinus rigida), and the mountain laurel (Kalmia latifolia).
The major determinant of the distribution of each of these species are as follows:
a) sweet buckeye – Aesculus flava, the sweet buckeye, does not occur anywhere within the glacial boundary, meaning that it is generally restricted to the eastern and southeastern regions of Ohio. This is perhaps due to issues with repopulation in “high-lime glacial tills.” Also, it is thought that “perhaps climate is the controlling factor here, for no geologic discontinuity is known along the edge of its distribution.”
b) hemlock – Tsuga canadensis, the eastern hemlock, is also present almost solely in the unglaciated regions of eastern Ohio but unlike the sweet buckeye, extends far to the north. The major determinant of the distribution for this species is that it appears to be restricted to “continuously cool, moist environments” like the bottom of valleys–which are abundant throughout this region.
c) rhododendron – Rhododendron maximum, the rhododendron is suggested to have belonged to “the mixed mesophytic association in Ohio,” although this particular species does not occur everywhere within the unglaciated regions of Ohio. A link has been found between this particular species and the ancient Teays river system, being that the rhododendron represents “one of several that lived (and still lives) amongst the Appalachian highlands”, that had migrated through this river system from northern to southern Ohio.
Observed Plants
Substrate-associated Plants:
This is the chestnut oak! Its leaves can look eerily similar to that of the chinquapin oak (Quercus muehlenbergii), but can be differentiated based not only on geographic location (as the chestnut oak is most typically found in southern/southeastern regions within Ohio), but also the teeth of the leaves. Chestnut oaks generally will have rounded teeth, while the chinquapin oak has “sharp leaf teeth” (Petrides, George A. 1972, Trees and Shrubs of Northeast and North Central US and Southeast and South Central Canada (Peterson Field Guide). Houghton Mifflin, 220 pp.).
According to the Lady Bird Johnson Wildflower Center, the chestnut oak is used as an ornamental shade tree for human use, and it was once used for tanning leather due to the “high tannin content” of the bark. For wildlife, the acorns of this particular oak serve as a food source for “turkey, ruffed grouse, songbirds, deer, and small mammals.”
I apologize for the orientation of this photo, but this is the sourwood! According to A Field Guide to Trees and Shrubs, the sourwood is the only member in its family (Ericaceae; the Heaths) to be a “full-size tree with flower and fruit clusters” (Petrides, George A. 1972, Trees and Shrubs of Northeast and North Central US and Southeast and South Central Canada (Peterson Field Guide). Houghton Mifflin, 289 pp.).
According to the Lady Bird Johnson Wildflower Center, the sourwood is “an attractive ornamental throughout the year” and the common name ‘sourwood’ is in reference to the tart, acidic taste of the foliage of this tree. Also, sourwood honey is a real thing! Bees really like this particular species.
Here is a photo of the foliage of an eastern hemlock that we found during our field trip! According to A Field Guide to Trees and Shrubs, Tsuga canadensis makes for a very poor Christmas tree, as the leaves fall immediately upon drying, but the wood was once extremely useful for making railroad ties, as it holds “railroad spikes exceptionally well” (Petrides, George A. 1972, Trees and Shrubs of Northeast and North Central US and Southeast and South Central Canada (Peterson Field Guide). Houghton Mifflin, 21-22 pp.).
According to the Lady Bird Johnson Wildflower Center, the eastern hemlock is a “graceful shade tree and ornamental,” which can be trimmed to form hedges as well. Also, along with being used for railroad ties, the bark was “once a commercial source of tannin in the production of leather.”
We will revisit this particular species further down on this page.
This is a photo of a deerberry shrub that our class stumbled across! According to A Field Guide to Trees and Shrubs, deerberry fruits are a delightful treat when “stewed and sweetened,” and that gray fox and ruffed grouse enjoy the wild fruits. This species has many other similar blueberry siblings within its family, Ericaceae (the heath family), which can sometimes be hard to differentiate; note the thin, untoothed leaves that typically have a white-hairy underside (Petrides, George A. 1972, Trees and Shrubs of Northeast and North Central US and Southeast and South Central Canada (Peterson Field Guide). Houghton Mifflin, 280-281 pp.).
According to the Lady Bird Johnson Wildflower Center, this species is a “variable species,” most likely due to hybridizing with others.
Ferns:
This is the Cinnamon fern. According to the Ohio Plants website, it has a holodimorphic frond type, which means that species of this type produce very obviously different types of fronds that are specifically grown to produce spores (the brown stalks toward the center of the plant)! Further, this individual has a pinnate-pinnatifid frond dissection type, which means that the fern is entirely separated into leaflets, which are lobed as well. Finally, this fern has a false indusium type, meaning that the “indusium” is essentially the entire margin of non-sterile fronds, which are curled to protect the sori (the spore production case).
This is the New York fern! According to the Ohio Plants website, it also has a pinnate-pinnatifid frond dissection type. As for the frond type itself, it is monomorphic (meaning the spores of this species can simply be found beneath the leaves). Also, the indusium type of the New York fern is reniform, meaning that it is kidney shaped.
Invasive Plants:
This is multiflora rose, an extremely invasive and awfully prickly plant. Although their flowers are very pretty, multiflora rose “grows aggressively and produces large numbers of fruits” that are then eaten by wildlife and quickly dispersed, according to invasive.org.
Referencing an article from the University of Connecticut, multiflora rose is native to “China, Japan, and Korea.” Also, this species can grow fairly tall, while also spreading across a fairly wide area, creating an “impenetrable thicket” that negatively impacts the growth of other plants that surround it. According to the same source, it is recommended that when attempting to remove multiflora rose, one must ensure that the “entire root crown is extracted to prevent regrowth.”
Pictured above is Japanese stilt grass, which is also extremely invasive. According to the National Invasive Species Information Center, Japanese stilt grass is native to Asia and was introduced to the United States around 1919. The impact of this species is that it tends to crowd other native plants due to the dense nature of its growth patterns.
According to the Penn State Extension, the best method of control is “to prevent seed production.” In order to do so, you must catch on to this pests growth fairly early on! Also, it is said that keeping your lawn properly mown (not mowing the grass too short) can help prevent the growth of this species. Chemical control is an option, but according to the same source, hand-pulling these weeds can be successful at complete removal due to the “plant’s shallow root system.”
Plant with unique physiology:
This is bear corn! I had never heard of this species before this field trip, so it was pretty exciting to see. Bear corn in particular is different from your typical photosynthesizing plants, being that they are parasites that grow on tree roots–typically oak trees (Newcomb, Lawrence. 1989, Newcomb’s Wildflower Guide. Little, Brown and Company. 18 pp.). According to Learn Your Land, although this species is a parasite, it does not harm the trees whos roots it sprouts from!
Typically, plants that undergo photosynthesis contain chlorophyll. The bear corn does not have chlorophyll (hinted at by their darker color), so it pulls the necessary nutrients from oak tree roots, due to the inability to create their own sugars! Finally, bear corn belongs to the Orobanchaceae family, the broomrapes.
Trees in Trouble:
This is the butternut (or white walnut) and it is one of our “trees in trouble.” According to the University of Wisconsin-Madison, this species is facing a disease called butternut canker, which is a fungal disease. The first case of butternut canker in the United States was recorded in 1967 and is believed to have been introduced to the U.S., originating elsewhere.
Butternut canker can be easily recognized as it leads to white walnut bark being left with a “mangled appearance.” This mangled appearance is due to the cankers that grow on the tree, eventually cutting off necessary nutrients, leading to the death of the tree itself. There is no cure to this disease, but action can be taken by removing “the affected branches” which can slow the spread of this disease throughout the entire tree.
As was stated earlier, this is the eastern hemlock! Sadly, it too is a part of our “trees in trouble” list. According to the New York State Department of Environmental Conservation, the main threat to this species is the hemlock woolly adelgid, which is a sort of aphid-like organism. To identify the presence of hemlock woolly adelgids, one would simply need to look at the underside of branches to notice a “woolly mass” beneath the needles.
From the New York State Department of Environmental Conservation as well, other signs of hemlock woolly adelgid presence include: “white woolly masses about one-quarter the size of a cotton swab on the underside of branches at the base of needles”, needle and branch loss, as well as obvious gray tinted needles. As for the management of hemlock woolly adelgids, biological control seems to be the most effective and efficient method. Various insects have been introduced to attempt to control these organisms by feeding on them and while the chemical control of these HWAs is possible, it is not very practical, especially in a “forest setting.”
Individual Assignment – 2 Flowers with Radial Symmetry:
This is the common cinquefoil, the first radially symmetric flower that I noted during this trip. Referencing the Newcomb’s Wildflower Guide, this species can be identified by their five leaflets that are toothed, as well as the brilliant yellow and radially symmetric flower that this plant produces (Newcomb, Lawrence. 1989, Newcomb’s Wildflower Guide. Little, Brown and Company. 240 pp.).
Additionally, this particular flower attracts rather large amounts of native bees, according to the Lady Bird Johnson Wildflower Center.
Finally, this is a photo of the flower of blue-eyed grass! According to the Newcomb’s Wildflower Guide, this species can be found in “fields and meadows,” and can be recognized by their six “pale-blue or white flowers” that are radially symmetric. Also, it can be noted that their “leaves are about as long as the flowering stems” (Newcomb, Lawrence. 1989, Newcomb’s Wildflower Guide. Little, Brown and Company. 332 pp.).
From the Lady Bird Johnson Wildflower Center, these plants can grow up to fifteen inches in height and this species is a member of the Iridaceae (iris) family.