Substrate Associated Plants:
Near the beginning of our trip, we visited the top of a hill with acidic sandstone substrate. Due to the low pH of the soil, many of the plants there were acidic soil specialists, only growing in areas with acidic soil.
First up, the Sourwood (Oxydendrum arboreum). Sourwood is a tree with simple, alternately arranged leaves that have finely serrate margins (Woody Plants of Ohio). We saw it growing interspersed with mosses and lichen at the woody edges of the hilltop field. In the past, Sourwood wood has been used to make tool handles and sled runners, but what its most known for is its honey (UK Horticulture). According to Killer Bees Honey, Sourwood honey is so distinct (and presumably tasty) that it regularly wins worldwide honey competitions!
Next, we saw Huckleberry-Blueberry bushes (Vaccinium sp.). These were out in the open field on the hilltop, next to a pile of fallen wood. Since I’m not sure which species of Vaccinium they are, I’ll talk about the genus as a whole. Vaccinium contains not just blueberry and huckleberry bushes, but cranberries and others too! The most obvious human use for this genus is eating, as some some Vaccinium berries are common to find in the grocery store, but there are other uses too. Namely, the plants are used by various Native American groups for ceremonial or medicinal purposes (NEAB).
Up third is the Chestnut Oak (Quercus montana). These were seen growing in the woods and woods’ edges. Unsurprisingly, their name comes from their leaves’ similarity to those of Chestnut trees. According to an Ohio DNR page, Chestnut Oaks are only found in the eastern, Appalachian, areas of Ohio, and they often grow in dry, rocky, acidic soils where they outcompete other plants. Similar to many other oaks, the Chestnut Oak has applications in tanning leather due to its high tannin content (Wildflower Center).
And finally, we have the Mountain Laurel (Kalmia latifolia). We saw this bush clinging to the side of a cliff where it was growing. Unfortunately, this was not the correct time of year to see it in flower. According to Penn State, the Mountain Laurel is the state flower of Pennsylvania. However, to me that seems like the least interesting thing about it! The Mountain Laurel is also being studied for its unique pollination mechanism. According to one study, when bees land on the flower to search for nectar, it dislodges the flower’s antheridium, which swings like a catapult to launch pollen onto the bee (Penn State). Also, Mountain Laurel is highly poisonous to humans and livestock. When bees who primarily feed on the flowers of Mountain Laurel produce honey, even the honey is toxic when consumed, and is colloquially referred to as “Mad Honey” (JAMA).
Ferns:
On our trip we also saw plenty of ferns, and learned about the terminology and features used to differentiate them. One of them was the Christmas Fern. The Christmas Fern has hemidimorphic, pinnafid fronds. Hemidimorphic ferns produce spores on part of a frond, but not the whole frond, and pinnafid ferns have fronds with leaflets that aren’t completely separate from one another. These features together, along with spores being produced on the underside of leaflets, help to separate the Christmas Fern from other species.
One of the others we saw was the Cinnamon Fern. This fern has holodimorphic, pinnate-pinnafid fronds. Holodimorphic ferns have have separate sterile fronds that do not produce spores, and fertile fronds that do produce spores. Pinnate ferns have leaflets that are completely separated from one another, and pinnate-pinnafid ferns have leaflets that are completely separate from one another, but are also partially divided. The large, meter long fronds and the cinnamon-colored, spore producing fronds make the Cinnamon Fern very easy to separate from other species.
Appalachian Gametophye:
Vittaria appalachiana, or the Appalachian Gametophyte, is a very unique species of fern, primarily for one reason: it doesn’t have a sporophyte. In the vast majority of ferns, the gametophyte is a small, short-lived stage, which produces a much larger sporophyte that we recognize as a fern. However, somewhere along the way, this species of fern lost the ability to produce its sporophyte, leaving the gametophyte as its only life stage. The Appalachian Gametophyte lives in sandstone outcrops in the Appalachian region of the US, far from the tropical habitat of most members of its genus, reproducing asexually through gametophyte-produced propagules called gemmae.
Since fern gemmae are larger than spores (typically 0.1-1mm long), they are considered too large to be dispersed by wind. Due to this, some have theorized that they could be dispersed short distances by water, or animals. According to a 1995 paper by Kimmerer and Young, Bryophyte gemmae can be dispersed by slugs, or (according to a 2005 paper) ants! These are also possible dispersion methods for fern gemmae.
The idea that gemmae of the Appalachian Gametophyte cannot disperse long distances is supported by their current distribution when compared to the geologic history of the Eastern US. Specifically, the Appalachian Gametophyte is only found in areas that were unglaciated during the last glacial maximum, despite transplant studies showing that it is capable of surviving in formerly glaciated areas with similar habitat. Additionally, the Appalachian Gametophyte has not dispersed to manmade habitat within its current range, such as rail tunnels, or cliff faces crated during the construction of highways. The Appalachian Gametophyte’s range and lack of further dispersion into formerly glaciated areas indicates that it lost its ability to disperse long distances, and thus, make sporophytes, sometime during or before the last glacial maximum. This inability to disperse into viable habitat indicates that the Appalachian Gametophyte is not being sustained through long-distance dispersal from a tropical sporophyte source. Additionally, phylogenetic data shows that its lineage has resulted from only one dispersion event.
Grr-Arghh! Plants:
Unfortunately, not everything we saw in Hocking Hills was a native species. In particular, we saw two invasive species: Multiflora Rose and Japanese Stiltgrass. Multiflora rose was originally introduced to the US for rootstock, erosion control, and as a living fence. Since then, it has spread across the Eastern US, and now covers more than 45 million acres (Amrine, 2002). Multiflora Rose establishes on hillsides, along woods’ edges, and in open areas, where it forms dense thickets and outcompetes native species. It also reduces land area for livestock pastures. According to the 2002 paper, a number of accidentally introduced biological control agents are currently spreading with significant effects on populations of Multiflora Rose. Since each mature plant can produce 500,000 seeds each year and leave seedlings sprouting for up to 2 decades, it may still be many decades before Multiflora Rose is naturally eradicated (Amrine, 2002).
The other invasive species we saw, Japanese Stiltgrass, is thought to have been originally introduced in the early 1900s through use as packing material in shipments from China (USDA). According to the USDA, its main ecological impact is crowding out native plant species in wet, shady environments. To control Japanese Stiltgrass, the SE-EPPC recommends cutting plants as close to the ground as possible once they are in flower, or the use of pesticides.
Trees in Trouble:
An unexpected species we saw on the trip was the Chinese Chestnut. Chinese Chestnut trees were planted in many areas due to their resistance to Chestnut Blight. A close relative of the Chinese Chestnut, the American Chestnut, was originally very common across most of the Appalachians and surrounding areas, and was prized for both its lumber and chestnuts. However, once Chestnut Blight was accidentally introduced from Asia in the early 1900s, it quickly spread through American Chestnut populations and all but eradicated them (NC State). Today, all that remains of the American Chestnut is young saplings, which sprout from the roots of trees that were originally infected by the fungus many decades ago. Since Chestnut blight doesn’t affect the roots of the trees, they endure a Sisyphean existence, repeatedly attempting to regrow only to be felled by Chestnut Blight each time. This disease leaves both the American Chestnut and Appalachian forests shadows of their former selves, a once great tree now only a small bush and a forest without one of its largest and most common inhabitants. However, there is hope. Various organizations and universities have been working on methods to give the American Chestnut resistance to Chestnut Blight. According to NC State, one group has been hybridizing the American and Chinese Chestnuts, repeatedly backcrossing them with more American Chestnuts until only a small portion of their genome, including the part that gives Chinese Chestnuts resistant to Chestnut Blight, comes from the Chinese Chestnut. Another group, from the State University of New York, has been using a different method to give American Chestnuts resistance. Instead of hybridizing the trees, they’ve taken a gene from wheat that breaks down a chemical used by the fungus to spread through its host tree (NC State). This leaves a nearly unchanged American Chestnut genome that is completely resistant to Chestnut Blight. Both of these projects are currently waiting for approval from various government agencies to begin restoring American Chestnut populations across the Appalachians.
Goldenrods:
My individual assignment for the trip was to find and identify two species of Solidago, otherwise known as goldenrods. The first goldenrod we saw was in a swampy area of the forest near lots of Cinnamon Ferns. This was the Rough Leaved Goldenrod, which can be identified by its solitary, branching stems of many flower clusters, and extremely large leaves at the base of the plant. Next, in a hilly field, we saw a Hairy Goldenrod. This one was a little more tricky to identify, but we eventually pinned it down to the Hairy Goldenrod by the dense hair on its leaves and stem.
Extra Photos:
Not pictured: Lots of salamanders/newts, and many other cool insects/plants!
Woody Plants of Ohio – https://dendro.ohioplants.org/sourwood/
UK Horticulture – https://www.uky.edu/hort/Sourwood
Killer Bees Honey – https://www.killerbeeshoney.com/blogs/musings/why-is-sourwood-honey-so-unique
NEAB – http://naeb.brit.org/uses/search/filtered/?string=vaccinium&tribe=&use_category=1
Ohio DNR – https://ohiodnr.gov/discover-and-learn/plants-trees/broad-leaf-trees/chestnut-oak-quercus-prinus
Wildflower Center – https://www.wildflower.org/plants/result.php?id_plant=QUMO4
Penn State – https://extension.psu.edu/mountain-laurel#:~:text=Governor%20Gifford%20Pinchot%20dubbed%20mountain,have%20also%20played%20a%20role.
JAMA – https://jamanetwork.com/journals/jama/fullarticle/371384
Amrine, 2002 – https://wiki.bugwood.org/Archive:BCIPEUS/Rosa_multiflora#Pest_Status_of_Weed
USDA – https://www.invasivespeciesinfo.gov/terrestrial/plants/japanese-stiltgrass
SE-EPPC – https://www.se-eppc.org/manual/japgrass.html
NC State – https://content.ces.ncsu.edu/chestnut-blight