Herbarium Help: Figuring Out Unknowns

The second part of my research this summer is dealing with the data, both my data from this summer and data from previous years. Part of this means trying to figure out the identify of our “unknowns:” plants that are particularly hard to identify out in the field. Most of the problem comes down to the fact that the majority of the plants we’ve been trying to identify are juveniles less than four years old. There are almost no manuals on how to identify juvenile plants, which can look very different from the adults, so we’ve had to figure most of these out on our own. Each year’s research students working on this project have figured out how to identify a new group of problem plants and their contributions have been invaluable to my research.

Earlier this summer, I realized that no one had figured out whether or not the ash trees in the College Woods are Fraxinus americana (White Ash) or Fraxinus pennsylvanica (Green Ash). All of the documents I’ve looked at have said something different. To figure this out, I’ve been trying to compare the plants in our plots with herbarium specimens of the two species.

An herbarium functions basically as a library of preserved plant specimens. They’re very helpful when trying to identify an unknown plant, or when studying something through time. This is because the specimen gives information on what a plant looked like at a certain time and where it was located. Unfortunately, the ash specimens the William and Mary herbarium owns have not yet given me any insight into the ash problem. All of the differences between the two species seem to be in the fruit and mature twigs, but all of the individuals in our plots are juveniles under 6 inches tall. Hopefully with more research I’ll be able to find something I can use.