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

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