Deep woods, the Appalachian Gametophyte, Ohio geobotany

We went to this exciting place called the ‘Hocking Hills,’ located in Logan OH. It was a beautiful location with so many interesting species of plants and trees. Some of the species that I was able to find were these acid sandstone plants which are the type of plants which thrive to grow in acidic environments; i.e. Acid soil. 

So this first one is the Sourwood which is a deciduous tree that is native to the Eastern United States. Its leaves have a sour taste — hence the name. It has white,, yellow, and green flowers which bloom during the summer time.

The second one is the American hornbeam which is also a deciduous tree, usually used in tool handles and levers due to its heavy, hard, and strong qualities. The tree also provides shelter and food to birds. The broad branches make it an excellent nesting and roosting site for many species, and is particularly popular with the ruby-throated hummingbird. In late summer, it produces small nuts which are enjoyed by goldfinches and various other birds.

The third one is the Chestnut oak  tree which is infrequently used for the timber it may provide since the tree often does not grow completely straight and usually has multiple branches. DUe its high tannin content in the bark, this tree was used extensively to tan leather prior to the 20th century and the wood would be discarded. Today we use the wood to some extent for fence posts and firewood. 

The fourth species that I found was the Eastern hemlock. A tree that takes up to 300 years to reach adulthood. Also, can live upto another 100 years if conditions are right.     Some of the other names for this majestic species include hemlock spruce and Canada hemlock. This tree makes an important nesting site for different wild animals, including birds. The evergreen foliage offers shelter, particularly during the winter months when deciduous trees lose their leaves.

The eastern hemlock is severely affected by the hemlock woolly adelgid (Adelges tsugae) which is a small invasive pest often found on the underside of the hemlock needles, where it sucks out the sugar from the tree. They look similar to aphids, and they multiply and spread quickly. Because of this, they can take over an entire tree and consume the sap out of it in a single season, causing the tree to dry up. With no natural predators to manage the spread of this destructive pest, the most effective method is spraying a nontoxic pesticide, namely horticultural oils and insecticidal soaps. These are sprayed on the tree and basically smother the HWA.

The American chestnut is a rapidly growing deciduous hardwood tree, historically reaching up to 98 feet in height. It is categorized as an endangered species by the IUCN. The tree is affected by a fungus and the disease is called the Chestnut blight. The fungus is a pathogen Cryphonectria parasitica, it is an ascomycete, and produces perithecia in small stromata. They can appear at any time of year when conditions are suitable. The perithecial necks are very long and come together where they protrude through the bark. The ascospores are forcibly ejected and wind-dispersed. Within the range of environmental conditions found in the geographic range of chestnut, there do not appear to be important differential effects of the environment. Environmental conditions are conducive to disease throughout the range of chestnut. Quarantine and eradication are two management approaches that are often attempted with non-native diseases. Quarantines, unfortunately, were applied after the invasion of Europe and North America.

A dead American chestnut tree


Here’s a closer look into its leaf


The origin of the Appalachian gametophyte has long been a mystery, in the excerpt from “Flora of West Virginia,” by P.D Strausbaugh and Earl L. they concluded that the “Appalachian gametophyte” is a prothallial stage of Vittaria lineata. They also suggested that these plants resemble lichens in their gametophyte stage and that the sporophytes resemble agla. According to the American Journal of Botany article, through analyses of plastid and nuclear data sets, their study demonstrates that a hybrid origin for V. appalachiana is unlikely. Instead, it appears that this species emerged from within the V. gramilfolia lineage.

The common name of V. appalachiana is Appalachian shoestring Fern, this species has a special from of asexual reproduction in which it produces structures called gemmae cups which are the vegetative propagules consisting of a few cells that are produced along the margins of the gametophytes. When mature these gemmae can separate from the gametophytes, disperse short distances, and grow into new independent, but genetically identical, individuals. The fern gemmae are quite large in comparison to spores, typically 0.2-1.0 mm in length and are generally considered too large for long-distance wind dispersal. Instead, gemmae are likely dispersed short distances by wind, water, or possibly by animals (in bryophytes gemmae dispersal has been shown to be facilitated over short distances by slugs and potentially ants [Kimmerer and Young, 1995] and potentially by ants [Rudolphi, 2009]). The notion of limited dispersal capability in V. appalachiana is also supported by the absence of this species north of the extent of the last glacial maximum ( Farrar, 1978 ), beyond which a transplant study has shown they are able to survive ( Stevens and Emery, 2015 ). Even recently disturbed areas (e.g., road cuts and tunnels) or other substrates that appear suitable within the range of V. appalachiana frequently remain uncolonized, while the species flourishes on seemingly similar substrates close by ( Farrar, 1990 ). Taken together, these data suggest that spore dispersal from a fully functioning sporophyte must have been responsible for the current distribution of V. appalachiana . The truncated range of this species in southern New York likewise indicates that the gametophytes lost their ability to produce mature, function-ing sporophytes sometime before (or during) the last ice age.

Scavenger hunt

The scavenger topic I was given was to find 2 examples/ species of frond forms (ferns). Ferns have two types of fronds, fertile fronds (leaves with sporangia) and sterile fronds (leaves lacking sporangia). However, some ferns may have two kinds of leaves which are known as dimorphic. An example of dimorphic fern is the Cinnamon fern, Osmundastrum cinnamomeum. This fern grows in moist areas like swamps, bogs, and wet forests. I found one at the Hocking Hills State Park. 

The other type of frond I found was the Intermediate wood fern, Dryopteris intermedia. This is a bipinnate pinnatifid, meaning that the leaves are divided two times. This fern can grow easily in well-drained soils and can tolerate high humidity.