Serpentine! Serpentine!*

Last month, we (spouse & I) visited the Soldiers Delight Natural Environment Area, in Owings Mills, Maryland (just northwest of Baltimore) which “is comprised of 1,900 acres of serpentine barren. The area has over 39 rare, threatened, or endangered plant species as well as rare insects, rocks and minerals. … There are 7 miles of marked hiking trails.” We walked on the red, yellow, and orange trails — Choate Mine, Dolfield, and Red Run trails — shown on the trail map.



at this point, the trails through the woods were just behind a residential area


Though the Maryland Dept. of Natural Resources page referenced above calls Soldiers Delight a serpentine barren (and so does the Maryland Geological Survey, linked below)another MDNR page calls it serpentine grassland, which was dubbed “the barrens” by English settlers. I’m not sure whether these habitats are the same or not. (The U.S. Forest Service serpentine barrens webpage references only the habitat in the Klamath-Siskiyou region southwestern Oregon and northwestern California, but that may be because it’s a nationally managed serpentine area; Soldiers Delight is a state area).

Serpentine itself is

a mineral producing dry, nutrient-poor soil deadly to plants not specially adapted to its unusual chemistry. In folklore, the name ‘serpentine’ is attributed to the soil’s resemblance to a mottled greenish-brown snake dwelling on similar soils in northern Italy. The greenish soil color comes from fragments of the underlying bedrock containing magnesium silicate. Toxic to plants, as much as one-third of the bedrock may be made of magnesium. … High levels of magnesium in the soil block a plant’s ability to take in soil nutrients, especially calcium. Because they are shallow and low in organic material and clay, serpentine soils also cannot hold water or nutrients well. Serpentine soils often have pockets of naturally occurring heavy metals toxic to plants, such as chromium, cobalt, and nickel” (and iron).

It’s quite beautiful in a stark way.


Serpentine stone is used as a decorative building stone and for road material, but the chromite — “a significant accessory mineral in the serpentine” and in fact in Maryland occurring only in serpentine — found at Soldiers Delight in Maryland was mined from 1827 until 1860 to make ferrochrome and chrome: “During the 19th century Soldiers Delight and the Bare Hills district of Baltimore County were the largest producers of chrome in the world” (Wikipedia).

(note typo on sign – chronium instead of chromium)

Chromium is mainly used to make ferrochrome, which is used in making high-grade steel. Chromium is also used “as a refractory substance – chiefly as a lining in the basic open-hearth steel process, which produces three-quarters of the steel of the United States.”

Most of the mining was fairly small-scale, in small open pits; the Weir mine at Soldiers Delight, on the Ward’s Chapel Road, …. was the largest in the county, and the workings, which consist of two vertical shafts 60 feet apart, are said to have reached a depth of 200 feet” (Maryland Geological Survey).

Choate Mine airshaft behind fence
Choate Mine airshaft sign — the 30′ deep airshaft provided the mine with a second opening for ventilation.
Choate mine airshaft
narrow gauge rail track near Choate mine airshaft
another fenced airshaft
airshaft, or mine entry?


As noted above, serpentine areas support a number of rare plants and insects.  The MD Dept. Natural Resources website page says that Soldiers Delight is “one of the most species-rich” serpentine areas in the world.

The plant adaptations necessary to allow plants to live in this challenging environment include extra efficiency at absorbing calcium, avoiding heat by being very hairy or having specialized leaf types (like serpentine chickweed), preventing excessive water loss by rolling long, narrow leaves inward (e.g., little bluestem grass), and having extensive root systems. Streams and seeps also help “moisture-loving species to survive in the otherwise hot, dry grasslands.”

coming out of the woods into the field
grasses along narrow trail

Smilax must also be adapted to these difficult soil conditions. There are four kinds found at Soldiers Delight: Smilax rotundifolia (common greenbrier), S. glauca (glaucous greenbrier), S. hispida (bristly greenbrier), and the non-woody S. herbacea (carrion flower); I don’t know which of the first three it was (probably S. rotundifolia), but I saw it everywhere:



Also lots of shrubby sassafras (Sassafras albidum) :


I liked the oak trees, different from the ones we have in New Hampshire; there are many oak species at Soldiers Delight — Quercus alba (white oak), Q. ilicifolia (bear oak), Q. marilandica (blackjack oak), Q. montana (chestnut oak), Q. prinoides (chinquapin oak), Q. rubra (northern red oak), Q. stellata (post oak), Q.velutina (black oak) — 

I didn’t know which these were but Chris Hoess at Friends of the State Line Serpentine Barrens thinks they are blackjack oak, Quercus marilandica, whichtends to have very dark green, leathery leaves with an orange fuzz underneath.”


There were a few wet areas, more seeps than streams —


And then a stream between the woods and the field:



Some of the rare species in serpentine grasslands include true prairie grasses (little bluestem, Indian grass, purplish three-awn); serpentine aster (Symphyotrichum depauperatum), which actually evolved on serpentine soils; sandplain gerardia (Agalinis acuta), sometimes called sandplain false foxglove, found only at Soldiers Delight; the fringed gentian (Gentianopsis crinita); fameflower (Talinum teretifolium); the Edward’s hairstreak (Satyrium edwardsii) butterfly; a rare black pear-shaped beetle (Polypleurus perforatus); and “a brightly colored leafhopper species so new to science that it hasn’t yet been given a name,” only at Soldiers Delight. For more info: list of Soldiers Delight wildflowerslist of Soldiers Delight woody plantslist of Soldiers Delight graminoids (grasses, rushes, sedges, cattails).

I didn’t see the pink-flowered plants listed (the sandplain false foxglove or gerardia, or the fameflower), or the fringed gentian, but I wondered if I had spotted the serpentine aster, but Chris Hoess says no, the leaves are too long and there are too many rays in the flower petals; could be some common narrow-leaved aster or (particularly looking at the second photo) a small white aster like Symphyotrichum pilosum var. pringlei —


And I saw another false foxglove, Aureolaria flava (smooth false foxglove):

Aureolaria flava (smooth false foxglove)

Other plants I was happy to come across were common chicory (Cichorium intybus), which I think is gorgeous,


and also partridge pea (yellow) and a purple liatris (either L. spicata, dense blazing star, or L. graminifolia, grass-leaf blazing star):

Partridge pea (Chamaecrista fasciculata)
purple liatris

I came across lots of these little tiny brassicaceae rosettes; someone suggested they’re shepherds purse (Capsella bursa-pastoris), which is not on the wildflower list for Soldiers Delight (though they are listed as a plant at Nottingham Park Serpentine Barrens in Chester County, Pennsylvania). But I thought perhaps it was Arabidopsis lyrata (lyre-leaved rock cress) and Chris Hoess confirms.


I think this fungus is Trametes versicolor (turkey tail) but it could be Stereum ostrea (false turkey tail); I should have checked underneath for pores:  



No pear shaped beetle was seen (I don’t think the black beetles in the chicory are Polypleurus perforatus), nor the new unnamed leafhopper (if I had known about it, I would have been looking for it!), nor the Edward’s hairstreak (actually, I did see a hairstreak or two but couldn’t get photos), but I was happy this common buckeye butterfly remained motionless for me:


And this orb weaver spider, which didn’t stay quite as still and I didn’t bring my camera as close to it:


And we have these large milkweed bugs (Oncopeltus fasciatus) in NH (also orb weavers), but it was fun to see them in two instar stages on some milkweed:



I knew nothing about this place when we walked these trails; next time, I’m going to be looking more closely for some of the rare plants and insects found in these unusual, life-challenging serpentine areas.

Here’s some beer-bottle art? to end on. Rolling Rock — get it? :



(* Post title from the 1979 film “The In-Laws,” with Peter Falk and Alan Arkin. Hilarious.)


  1. mmwm,

    I think I can answer some of your questions. The term “barrens” is used pretty loosely in the eastern US for any patch of ground that will support neither a good crop or a robust forest. So in the east, a “serpentine barrens” could be anything from grassland through savanna to a scrub oak-pitch pine woodland. In the west, the serpentine can have a more pronounced effect, and a “barren” may really be free of vegetation.

    The shape of the oak leaves in the two pictures suggests that they’re blackjack oak, Quercus marilandica. This tends to have very dark green, leathery leaves with an orange fuzz underneath. It’s one of the “scrub oaks” common on the barrens-they resprout well from roots after fire.

    Unfortunately, the first aster pictured is not serpentine aster–leaves too long and too many rays to the flower. The second one might be, but I can’t tell for certain even from the enlarged photo–it might be another one of the small white asters, like Symphyotrichum pilosum var. pringlei. The little basal rosette, however, is almost certainly (judging from its habitat on the bare serpentine rock) lyre-leaved rock cress, now Arabidopsis lyrata.

    There’s a lengthy strip of serpentine running, irregularly, most of the length of eastern North America. From Georgia up to Staten Island, it tends to be exposed as grassland and savanna. Further north, its effects are attenuated by glacial till, but there’s a long strip of it that runs up the middle of Vermont and through Quebec to the Gaspe Peninsula, then jumps over to Newfoundland, where the Tableland of Gros Morne really is barren.


    Chris Hoess
    Chair, Friends of the State Line Serpentine Barrens

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