April 2017

It has warmed up quickly in Maryland this year.  I spent a lot of time surveying the limestone bluffs along the Potomac River which has a very nice spring ephemeral display.  In my previous season working at the canal I arrived after the peak of this floral display. Twinleaf is a prime example of one these spring ephemeral species.

Jeffersonia diphylla (Twinleaf) I don’t always catch this species with flower because they last for a short period of time.

I keyed out a couple new invasive plant species as well.  The first was Thlaspi alliaceum (Garlic Pennycress).  This weed seems well established in Maryland and probably has been for a while.  It has been described as a “newly invading species” by some in states such as Ohio as recently as 2015. It occupies acres upon acres of fallow agricultural fields in the Hagerstown Valley and occasionally occurs in smaller though still dense patches along the floodplain forest of the Potomac River.  These observations lead me to believe it prefers open sun and recently disturbed soil.  I have never seen it in upland habitats.  It looks similar to some other weedy species of the Brassicaceae family.  One of the better diagnostic characters of Garlic Pennycress is the slight garlic odor it emits when the tissue is broken.  It belongs to the same tribe as Alliaria petiolate (Garlic Mustard).

Thlaspi alliaceum (Garlic Pennycress) The light green in this photo is Garlic Pennycress flowering in the thousands in a farm field close to the canal.

The other invasive species is Lamium galeobdolon (Yellow Archangel).  I found a small patch along the Potomac River in central Maryland.  The Mid-Atlantic Exotic Plant team of the National Park Service recently released an invasive plant alert for this species in the region.  I reported the location of this species to the Park Biologist for eradication.

Lamium galeobdolon (Yellow Archangel) To my knowledge this is the first time this invasive plant has been recorded in the canal boundary.

The state Natural Heritage Program botanist was nice enough to meet me in the falls line area of Maryland to review several species of Amelanchier that he had done genetic testing on several years earlier.  Amelanchier nantucketensis is one of the G1-G3 plant species that I am focusing my surveying efforts on this season.  We found it in flower and he schooled me on some of the nuances of hybridization within this genus and their morphological character overlap.

Amelanchier nantucketensis (Nantucket Serviceberry) The short and narrow petals of this species are diagnostic. Interestingly, the petals will sometimes bare pollen.

I briefly visited the shale barrens of western Maryland as well and was happy to find a few of the endemic plants that grow there in flower.

Trifolium virginicum (Kate’s Mountain Clover) Shale Barren endemic


Coleman Minney

Chesapeake and Ohio Canal National Historical Park

Final visit to the shale barrens

My internship has concluded and it was a very good experience.  I had to leave earlier than I expected, which meant I didn’t get to visit every place in the park I wanted to, but things happen.  Perhaps I will visit again.  I found over 20 new populations of state-listed plants in the canal including 4 entirely new rare species.  I also found a population of Ptilimnium nodosum (Harperella) which is a federally-endangered plant.  Check out my previous entry for more details on that find.

I learned a lot about managing a large database of rare plants.  The amount of rare plant records for this park meant that I couldn’t possibly survey for all of them in one field season.  One challenge was prioritizing which plants to survey for.  I gravitated towards the shale barren habitats within the park.  I found these to be the most interesting to survey.

My last trip into the field was to survey a shale barren habitat.  I found a new population of the globally-vulnerable (G3) Trifolium virginicum.  This is one of the discoveries I was most excited about.  I can’t quite explain it but I really enjoy seeing this plant.  On this field trip I found a population with newly established clumps and one clump that had seedlings sprouting.  I was pretty excited when I saw this and considered it a fitting end to my internship experience at the Chesapeake and Ohio National Historical Park.


Trifolium virginicum. One clump of a new population I found on my last day of field surveying.












This picture shows the habit of the seed heads to hang down around the base of the plants. They blend in very well with the shale talus.



This is a closer view of the seed heads. If you look closely you can see the seedlings sprouting.


Coleman Minney

Field Botany Intern

Chesapeake and Ohio Canal National Historical Park

First air of autumn

This will be the final blog post of my internship.  One of the more interesting recent developments for me is finding Ptilimnium nodosum (Haparella) in the park in late July.  This is a federally-endangered plant in the Apiaceae (Carrot Family).  In the 2000s there was a major re-introduction effort within the canal between a professor at George Washington University and the National Park Service.   From my understanding this re-introduction was not successful at establishing new populations, but some useful knowledge was gained through the experience and seeds from it were acquired for long term preservation.  The last time a natural population was found on the main stem of the Potomac River was around 20 years ago.  I hope I am giving enough of an overview while practicing a fair amount of discretion due to the sensitive nature of this information.  I went to that location where it was last seen (a well-developed scour bar) and was surprised to find a decently-sized population in full flower.  I think one could describe this as a meta-population.


Ptilimnium nodosum. Each umbel was rarely larger than a dime.


Ptilimnium nodosum. Even in flower these plants were hard to see. They grew alongside numerous wetland graminoids such as Juncus spp.


Ptilimnium nodosum. The leaves are referred to as phyllodes (reduced leaf petioles). They are hollow and segmented.











As I mentioned in a previous entry, the Potomac at this time of year is usually at its lowest point.  I was able to walk out into the middle of the river and could have crossed into West Virginia on the other side if I desired.


From the middle of the Potomac in late July. The green is Justicia americana (Water Willow)

Another interesting plant I ran into with the help of a lady who has voluntarily been doing plant surveys along a portion of the canal for several years is the state-endangered Trachelospermum difforme (Climbing Dogbane).  Not only had I never seen this plant before this summer, but I had never even heard of it.  This plant is of particular interest to me because it resembles Japanese Honeysuckle morphologically and in growth habit.  As I discussed in a previous entry, the canal is very interested in developing a robust volunteer Weed Warrior program.  Part of my responsibilities involve educating these Weed Warriors about native look-alikes, especially state-listed species.  I must admit that this one is tricky at first and would especially be difficult to less experienced eyes.  Fortunately once you are aware of the plant, it is easily distinguished from Japanese Honeysuckle by its milky sap when leaves are present.  On the other hand I can imagine some difficulties for volunteers because the two can grow intermingled in each other.  This would be particularly hazardous if they are growing together, it’s late in the season and Japanese Honeysuckle is still green while Climbing Dogbane has gone dormant.  The “hazard” being that dormant Climbing Dogbane is mechanically treated by someone thinking it is part of a honeysuckle clump.


Trachelospermum difforme. The milky sap I mentioned earlier.


Trachelospermum difforme. In flower. The manuals state that leaf shape is variable. Some of the leaves were quite oribicular with an acuminate tip. They resembled Oriental Bittersweet leaves to my eyes, though that vine has alternate leaves.

IMG_9143 (2)

Trachelospermum difforme vs. Lonicera japonica (Japanese Honeysuckle). In my hand is Japanese Honeysuckle. As you can see the two grow alongside each other and can easily be confused as one species.

I went through the photos I took over the season and thought I would include some of the more interesting ones here for fun.

Io Moth caterpillar on Baptisia australis leaf

Automeris io (Io Moth) caterpillar on the state-listed Baptisia australis. Will sting you.

Eriocampa juglandis (Butternut Woollyworm) on state-listed Juglans cinerea (Butternut) leaf.

My internship still has a few weeks left but I feel the season waning.  The asters will have their time and fall will be here soon. Cheers to a successful field season.



Coleman Minney

Field Botany Intern

Chesapeake and Ohio Canal NHP

July in Maryland

There has been a prolonged stretch of hot, humid days here in Maryland.  This weather can make field work unpleasant at times but there is a silver lining.  The decrease in the amount of rain, which is normal for this time of year, allows the Potomac River to drop to lower levels.  This drop has implications for the rare plant survey work I am tasked with for my internship.  River scour habitats were a new concept to me when I first got here and read about them.  The idea of grassland maintained by erosion from flood waters on river islands and river edge habitats was something I never really thought about.  With the drop in water levels on the Potomac, surveying these river habitats has gone to the forefront in my mind.  In particular, the historical records of the federally-endangered Haperella (Ptilimnium nodosum) within the canal have caught my interest.  The last time this plant was seen on the Potomac was around 20 years ago.  Even though I know the chances of finding it are remote, I still can’t help but hold out a little hope.  This plant has a habit of popping up in random river scour bars one year and disappearing the next.  From the little exposure I have to these scour bars it seems apparent that the invasive plant Japanese Knotweed (among several other invasives) also thrives in this disturbed soil.  One of the harder parts of my internship is seeing situations where rare plants are under assault from invasives and knowing how best to contribute to dealing with the problem in a meaningful way in light of the limited time I will be here.


Looking upstream on the Potomac in western Maryland. The plant at the bottom of the photo is Water Willow (Justicia americana) which is very fond of growing on the edges of these scour bars.

The development of a Weed Warrior program was also one of the tasks of my internship.  Another intern and I will be giving a presentation on several invasive plants commonly found in the canal as well as control methods and native look-alikes for each.  I read a statistic in a published paper that stated 33% of the flora of the Mid-Atlantic region is considered non-native to the region or North America.  I was surprised by that number honestly.  It really underlines the importance of efforts like this for the National Park Service moving forward.  It also poses some difficulties in prioritizing how to develop a program such as this with limited time and resources to train volunteers.

This experience will no doubt be valuable to me as a person that wants to be a nature preserve manager one day.  The part I am looking forward to most is meeting one on one with the individuals afterwards and learning the challenges of maintaining a volunteer-led invasive control effort.  I also hope to learn how to tailor future educational exercises for volunteers interested in invasive removal as well as knowing who these people are and why they chose to volunteer in this particular way.

I haven’t done as much botanical surveying since my last post.  One reason for this is because I participated in a wetland plant identification course at the National Conservation Training Center in West Virginia last week.  This was a great experience.  Of the three instructors for the course, one was an author for Flora of North America and another had a major hand in developing the wetland indicator codes assigned by the USDA.  He also founded a herbarium.  Needless to say it was great being around so many knowledgeable botanists.  It was also nice talking to the other students in the class, many with permanent federal jobs, who had some helpful advice about seasonal work and graduate schools.

On one of the few trips I made into the field recently I snapped a couple interesting photos.


Purple Cliffbrake (Pellaea atropurpurea) This cool looking fern was growing in the masonry walls of one of the canal locks.


Common Water Snake. When I stumbled upon this snake I thought for sure it was a Copperhead. However, after seeing the rounded pupils of the eyes I knew it was not vemonous.

Coleman Minney

Field Botany Intern

Chesapeake and Ohio National Historical Park




Mid-summer Update

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.

Liparis liliifolia, Twayblade

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.

Heracleum maximum, Cow Parsnip

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.

Gymnocladus dioicus, Kentucky coffeetree

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.

Polygala polygama, Racemed Milkwort

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.

Paw Paw Tunnel, northern entrance


Coleman Minney, Field Botany Intern

Chesapeake and Ohio National Historical Park

Shale Barren site visit

The last part of April and early May have been very rainy here in Maryland.  The spring ephemerals have done their thing and the early summer bloomers are out in force.  A lot of sedges are on the verge of being ripe as well.  The field season is well in its prime.  I’ve seen some very nice displays including the fringe trees along the Potomac Gorge not far from Washington, D.C.


Chionanthus virginicus, Fringe Tree

One particular habitat that I have visited once and hope to more in the future is the Shale Barren.  It’s an Appalachian specialty.  They occur on relatively high elevation slopes, with shale parent rock, on generally southern aspects.  The barrens are maintained by the erosion of loose rock caused by streams below that undercut them.  This creates a very hot, dry, and rocky landscape.  Several plants are endemic to these areas.  They specialize in the extreme conditions and low competition from other plants.  Most of the endemic plants of the barrens have only been described in the last 100 years.


The slight white haze in the understory is Phacelia dubia flowering in the thousands.

The picture above is what I would consider to be on the periphery of the barren.  The more rocky and less vegetated center is not seen here.  This picture does show the general habit of trees that grow here in being slightly stunted.  When I first got here I thought to myself this looks like a recently burned area.  While fire may have played a role in enlarging these barrens, they are maintained naturally by erosion.


Astragalus distortus, Bent Milkvetch. The major distribution of this one is in the central U.S. but a disjunct population is limited to the Shale Barren habitat of the Appalachians.


Trifolium virginicum, Kate’s Mountain Clover. The distinctive vegetative character for this species is the length of the leaflets in relation to their width.

The Chesapeake and Ohio Canal runs 180 river miles across the state of Maryland and contains 200 or so state-listed species within it.  Because of this I have prioritized some species based on their global rank.  My target for instance on this occasion was Trifolium virginicum.  This species is listed with a G3 rank.  That means it is considered globally vulnerable and there may be as few as 80 occurrences on the entire planet.  For this particular species, each occurrence has a small number of individuals within the population.  I was lucky enough to relocate this record and found that the population is stable.  The last time the record was updated was in 1995.  I plan on visiting more shale barrens in the future to update records for a couple other G3 species that occur here.


Viola pedata, Birdsfoot Violet. This is not a shale barren endemic but I included it to show the rocky habitat and because I liked this particular plants flower coloration.

Occasionally you will stumble upon a plant that is common but because of its stature or pure happenstance you have never seen it before.  As many times as I have been botanizing in the woods of the eastern U.S. I have never come across the following plant.  I was happy to see it in flower and add it to my photo collection.


Obolaria virginica, Pennywort. Of the Gentian Family.

Also happy 100th birthday National Park Service.  I am looking forward to the centennial celebrations this weekend at the canal including the park-wide Bioblitz.


Coleman Minney, Field Botany Intern

Chesapeake and Ohio National Historical Park

Bottomlands and bluffs on the Potomac

I’ve almost completed the first week of my internship with the Chesapeake and Ohio Canal National Historical Park.  As a botany intern I am responsible for updating plant records for all the rare and threatened flora within the parks borders.  The park runs approximately 130 miles along a narrow corridor from the mountains of western Maryland to Washington, D.C.  I’ve spent most of my time here so far getting acquainted with the rich cultural history of the canal and the friendly staff at the park.  I’m immersing myself in the many publications on the natural resources of the area that sits on four massive shelves at the park headquarters.  In particular one publication has caught my fancy and I can’t put it down.  Some of the taxonomic names are out of date but the information it holds on the specialized habitats of the state and the plants within them is invaluable.  Shale barrens and limestone bluffs are especially interesting because this is where many of the plants I’m tasked with surveying for are located.


The first few days here involved various orientation tasks and I’ve only been in the field for a couple hours.  However, in that short time I got to see an impressive display of spring ephemerals and two state listed plants.


Delphinium tricorne, Dwarf Larkspur


Dodecatheon meadia, Shooting Star


I look forward to getting into the field more and more in the coming weeks.  The towpath that runs alongside the entirety of the canal offers great access to the entire park.


Moving forward I plan to schedule my surveying with the goal of focusing on the plants that are flowering currently or will be soon.  I also am tasked with getting the parks “Weed Warrior” program up and running. While the canal has its share of rarities and beautiful habitat, it also faces challenges including a fairly healthy crop of invasive plant species.

“Death is one thing…  an end to birth is something else…”

-M.E. Soule and B.A. Wilcox

Protecting rare and threatened plants has been a passion of mine for a while but the quotation above made the hairs on the back of my neck stand up.  After reading it I felt a renewed sense of urgency for the protection of our nations endangered species. It feels good to be in a position to make a positive contribution towards that end.


Coleman Minney
Chesapeake and Ohio Canal National Historical Park
Hagerstown, Maryland