It’s the mid-point of my internship here in Maryland. So far the experience has been fulfilling. The extent of the Chesapeake and Ohio Canal means that there is always some place new to explore. I wanted to highlight some of the new rare plant records I found since my last post.
It seems that many botanists hold high regard for the orchid genus no matter where you are. They are picky plants and that makes finding them, especially in flower, a real treat. I was surveying along the top of a limestone bluff on the Potomac River when I found the following.
This is a new species for the canal and is listed as threatened in Maryland. This type of orchid is called a Twayblade and its flower structure is quite intricate.
Earlier this month a park visitor reported a possible Heracleum mantegazzianum (Giant Hogweed) sighting. This invasive can be dangerous to humans if they come into contact with foliage or the sap of the plant. When I went to investigate the sighting I discovered that it was the relatively smaller native Cow Parsnip of the same genus. I put my hat in the picture for scale. Cow Parsnip is a plant of impressive proportions. It is actually a “watchlisted” species in Maryland so I documented the location and number of plants in this particular population. The population stretched for about a quarter mile along the towpath of the canal. Interestingly all the plants, which totaled around 500, were within 10 meters of the towpath. Because of its stature I thought it was odd that it had not been recorded within the canal before this year.
Not far from the Cow Parsnip I located another state listed plant, Gymnocladus dioicus or Kentucky coffeetree. The population consisted of two saplings along a road. Because a town was nearby and this species is planted occasionally as an ornamental, I do not believe these two saplings are part of natural population. This is one of the challenges of working in a park with a lot of urban areas along its boundary. Of course I would rather see native plants being planted as ornamentals rather than non-native ones. On a side note, the largest Kentucky coffeetree in the nation is located in Hagerstown, Maryland, where the park headquarters is.
And finally, I found a new population of Polygala polygama on the margin of a shale barren in western Maryland. There were over 50 clumps of this state-listed Milkwort growing directly under a power line in full sun. It’s interesting how man made disturbance can sometimes be beneficial to conservative plants like this one. It is obviously benefiting from the open habitat created from the power company’s efforts to keep the area under the power lines free of shrubs. It is also interesting to note that along the same power line a little farther down, invasive plants dominate that ground cover.
This week I visited the Paw Paw Tunnel. This tunnel is locally famous because of the engineering effort it took to construct it. The tunnel is almost a mile long, straight through a mountain. It was a strange experience to walk through it and imagine working as a laborer during its construction.
Coleman Minney, Field Botany Intern
Chesapeake and Ohio National Historical Park