Deep Woods, the Appalachian Gametophyte, and Ohio Geobotany
Plants associated with acid sandstone substrates according to Jane Forsyth in “Linking Geology and Botany: a new approach”
The genus Vaccinium, pictured above is an example of acid loving plants. Various species often look very similar and many hybridize, making them a bit difficult to identify. But not to worry, this genus contains blueberries, huckleberries, bilberries, deerberries, and cranberries, all of which are edible! (Petrides, George A. 1972, Trees and Shrubs of Northeast and North Central US and Southeast and South Central Canada)
Chestnut oak, Quercus montana is another acid loving plant. It has somewhat leathery leaves with round, shallow teeth. The bark is distinctively dark and deeply ridged and has formerly been used for tanning leather (Petrides, George A. 1972, Trees and Shrubs of Northeast and North Central US and Southeast and South Central Canada, Lady Bird Johnson Wildflower Center Native Plant Information Network).
A final acid loving plant, Sourwood, Oxydendrum arboreum. Sourwood is the only full sized tree with heath type flowers and fruits. The genus name meaning “sour tree” and common name refer to the sour tasting leaves (Lady Bird Johnson Wildflower Center Native Plant Information Network).
Ferns
Pictured below is a christmas fern (Polystichum acrostichoides). It has a fully pinnate frond dissection type, as the fern is fully divided into separate leaflets with rachis between the leaflets as can be seen below.
Christmas ferns are hemidimorphic, meaning the fronds are divided into a fertile portion and a sterile portion. This can be observed in the picture below, where only the terminal leaflets have sporangia.
The next fern I observed is a rock polypody, or Polypodium virginianum. This fern has a pinnatifid frond dissection type, meaning the frond is lobed (in this case deeply) but not containing entirely separate leaflets. This fern is monomorphic, meaning the frond produces spores on otherwise normal leaves.
The third fern I observed, pictured below, is called sensitive fern or Onoclea sensibilis. This fern has a distinct bipinnatifid frond dissection type, meaning the frond is twice-compound. It is holodimorphic meaning the fern produces completely different fronds, one dedicated to spore production (left in image) and one solely vegetative (right in image).
A description of the Appalachian gametophyte based on “Unraveling the Origin of the Appalachian Gametophyte” (Pinson and Schuettpelz, 2016).
- Vittaria appalachiana, commonly referred to as the Appalachian gametophyte, uniquely exists only in the gametophyte stage, reproducing asexually via gemmae.
- Fern gemmae are quite a bit larger than fern spores, making them less conducive to wind-dispersal commonly used by spores. Instead, gemmae can be dispersed short distances by wind, water or animals. As found in [Kimmerer and Young, 1995], gemmae dispersal may be facilitated by slugs for short distances.
- The distribution of V. applachiana is limited to areas of the last glacial maximum in areas with very similar, undisturbed substrate. Transplant evidence suggests that V. applachiana could survive in other suitable places nearby however, the population does not seem to spread to these areas. This suggests that the current distribution of V. applachiana is likely from a fully functioning sporophyte sometime before or during the last ice-age.
- The population of V. applachiana is likely not sustained by long distance dispersal because of genetic analyses of the populations which found relatively high levels of diversity in Ohio and Alabama as well as heteroxygosity for several alleles. This evidence suggests that the Appalachian gametophyte is a polyploid hybrid of ancient origin.
Grr-Arghh! plants.
Japanese stiltgrass (pictured above) is an invasive grass that came to Tennessee in 1919 and has since spread over much of the Eastern US. It is native to several countries in Asia including Japan, China and Korea, and likely came over as packing material. It is primarily found in moist areas such as flood-plains and woodlands and spreads aggressively in areas with disturbed soil. Japanese stiltgrass forms dense patches that displace native vegetation. Control measures include manual strategies such as removal by hand for smaller populations and mowing to deter reseeding as well as herbicide based control strategies (National Park Service & U.S. Fish and Wildlife Service. (2010). Japanese Stiltgrass. In Plant Invaders of Mid-Atlantic Natural Areas, 4th ed.) (Victoria Wallace et al. Invasive Plant Factsheet: Japanese Stiltgrass, University of Connecticut)
Trees in Trouble!
One tree in trouble that we observed was butternut or white walnut, Juglans cinerea. This species is threatened by a fungal disease called butternut canker. The fungus Ophiognomonia clavigignenti-juglandacearum causes large breaks in the bark as well as cutting off nutrient transmission causing dieback. There is no remedy for this fungal infection however, removing diseased parts of the tree can prevent the spread of the disease throughout the tree. (“Butternut Canker.” Wisconsin Horticulture)