May 2017

I never cease to be amazed at how different a rich forest habitat can look from spring to summer.  Rock outcrops on slopes of these areas that once stood out as clear as could be in spring are often covered in thick herbaceous level growth by this time of year.  Unfortunately in some cases this is because an invasive plant such as Garlic Mustard has reached maturity in such numbers as to obscure the ground level.  Native undergrowth in more stable areas can achieve the same effect.  I have been spending a fair amount of time surveying in cool, shaded, north-facing forests associated with limestone rock outcrops recently.  One of my priority target species, Arabis patens, occurs here.  The genus Arabis, and the Brassicaceae family in general, can be a difficult group of plants to identify.  Recent taxonomic treatments have placed some species previously found in Arabis into other genera such as Boechera, Borodinia, and Arabidopsis.  This only adds to the difficulty.

Arabis patens (Spreading Rockcress)

Arabis patens (Spreading Rockcress) This picture shows the fruit, sub-entire to entire middle cauline leaves, dentate lower cauline leaves and the smaller basal leaves. I’ve found that leaf size, shape and dentation varies among individuals.

These limestone bluff forests contain some interesting geological formations.

Jeffersonia diphylla (Twinleaf) is not a rare species in Maryland but it has caught my attention over the years because of the bad luck I’ve had trying to catch it while it is in flower.  Fortunately I was able to catch it this season as I discussed in a previous post.  I also ran into huge patches of it in May.  I have observed patches stretching for acres that have approximately 80 percent cover throughout.

Jeffersonia diphylla (Twinleaf) The seed capsule has opened and fallen over, spilling its seeds onto the ground.

Jeffersonia diphylla (Twinleaf) The seeds look like ovate popcorn kernels. The out of focus plant next to them is a Twinleaf seedling.

Some other species I’ve recently encountered in rich woods, although not necessarily in north-facing limestone associated forests, were Viola canadensis, Maianthemum racemosum and state-listed Panax quinquefolius  Panax quinquefolius (Ginseng) is a well-known plant in the Appalachian region.  Because of its commercial value it has been extensively harvested throughout its range.   This exploitation has earned it a G3G4 global ranking from NatureServe.  I find this plant’s foliage quite attractive and its presence in an area usually indicates the habitat is stable and possibly high quality.

Viola canadensis (Canada Violet) This species can reach over two feet in height. The yellow throat of the flower is a diagnostic character.

Maianthemum racemosum (False Solomon’s Seal)

Panax quinquefolius (Ginseng)

I caught another well-known plant, although for much different reasons, in flower recently.  Toxicodendron radicans (Poison Ivy) is a common vine that for whatever reason I don’t see in flower often.

Toxicodendron radicans (Poison Ivy)

Lastly, May 19th was Endangered Species Day.  I participated in a youth event held in Cumberland, Maryland that discussed rare species with groups of 4th graders.  I got a kick out of one child who attempted to explain how “Bigfoot” was a rare species.

Coleman Minney

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