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MARY Plant of the Month

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November 2015

Najas minor Allioni

Common Name: Brittle waternymph, brittle naiad

Family: Najadaceae

Identification: Najas minor is a non-native species that has become common in Maryland’s freshwater habitats. All species of Najas have roughly linear leaves with small teeth and a sheathed base. In mature specimens of Najas, the leaves often become recurved. Najas minor can be distinguished from other species of Najas by the nature and number of the leaf teeth: Najas minor has multicellular teeth and generally fewer than 15 teeth per side (Block and Rhoads 2014). Immature specimens of Najas minor can be difficult to distinguish from other species.

Ecology:Najas minor is a submerged aquatic plant found in a variety of freshwater habitats. It seems to be relatively widespread in Maryland, though it remains poorly documented.

Distribution:Najas minor has been reported from Florida to Vermont and west to Oklahoma and Texas. USDA also reports the species from California (see below).

Image courtesy of the USDA Natural Resources Conservation Service

For county records of Najas minor, go to:The Maryland Biodiversity Climacium americanum Species Page.

References: Block, Timothy A. & Ann Fowler Rhoads (2011) Aquatic Plants of Pennsylvania; A Complete Reference Guide. University of Pennsylvania Press. 308 pp.

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October 2015

Climacium americanum Bridel

Common Name: Palm tree moss

Family: Climaciaceae

Identification: Climacium americanum is rather extraordinary among mosses in that the horizontal stems grow beneath the soil surface with branches that extend a few centimeters above the ground – like tiny trees. In flooded areas, C. americanum will grow horizontally along the surface of the ground. The species can be confused with a close relative C. dendroides (Hedwig) F. Weber & D. Mohr, although they differ in the shape of the leaves, particularly the leaf bases (Eckel 2015).

Ecology: Climacium americanum grows in damp soil.

Distribution: Climacium americanum is relatively common in Maryland. It can be found on the East Coast from Newfoundland to Florida and west to Washington State (Eckel 2015).

Image courtesy of the USDA Natural Resources Conservation Service

For county records of Palm tree moss, go to:The Maryland Biodiversity Climacium americanum Species Page.

References: Eckel, Patricia M., 2015. Climaciaceae in Flora of North America. Vol. 28. eFloras species page.

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March 2015

Rudbeckia hirta L.

Common Name: blackeyed Susan

Family: Asteraceae

Identification: Blackeyed Susan has solitary flowers with a dark brown center and bright yellow rays. It differs from other related species by having dense stiff hairs on the stems and leaves. It grows to nearly one meter tall. There are two varieties of Rudbeckia hirta in Maryland var. hirta and var. pulcherrima.

Ecology:Blackeyed Susan is common in fields and along roads throughout Maryland. It is biennial or a short-lived perennial.

Distribution:Rudbeckia hirta var. hirta is native along the East Coast from Maine to Georgia and west to Illinois. The variety pulcherrima is also found in this region and farther west. For information on the varieties of Rudbeckia hirta, refer to the recent Flora of North America treatment.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of blackeyed Susan, go to:The Maryland Biodiversity Rudbeckia hirta Species Page.

Broader interest: Rudbeckia hirta is the state flower of Maryland and is used in ceremonies celebrating the State. It is traditional for the winner of the Preakness Stakes in Baltimore to be wreathed in blackeyed Susans. However, since they are out of season, the wreath is made of chrysanthemums painted to look like blackeyed Susans (Rudbeckia hirta on Wikipedia).

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February 2015

Alternanthera philoxeroides (Mart.) Griseb.

Common Name: Alligatorweed

Family: Amaranthaceae

Identification: Species identification from a distance can be problematic; one needs to see the flowers and leaves clearly to distinguish this species from other wetland plants. The plants are generally found in shallow water and, according to Weakley (2012), the plants may float as mats on the water’s surface. The flower stems are emergent and hollow. The flowers are white and clustered in small, 0.5-1.5 cm tufts at the end of a short stalk originating at the stem nodes. Individual flowers have 5 tepals. The leaves are opposite and elliptic with distinctive, pinnate veins.

Distribution:Alligator weed is an aquatic plant native to South America. It has been introduced to many regions of the world including the United States. It is considered a noxious weed in several southeastern US States (USDA Plants Database ). It was previously known from neighboring areas of Virginia (Weakley 2012), where it is spreading rapidly (Weakley et al. 2012). The species is able to grow in a variety of habitats including brackish wetlands and freshwater streams and ponds (Weakley 2012). This makes the species a serious concern for Maryland’s wetlands.

Maryland Spottings: Alligatorweed was encountered Along the C & O canal in July 2014 (source). This is thought to be the first confirmed report of the species in the State of Maryland. It was later spotted independently in a shallow, inland pond in Prince Georges County in September, 2014. The species has been previously reported along the Potomac River (on the border of Maryland and Virginia) and from neighboring areas of Virginia (Weakley et al. 2012). Voucher specimens have been accessioned at University of Maryland (MARY) as well as with the Maryland Department of Natural Resources (TAWES).

Image courtesy of the USDA Natural Resources Conservation Service

If encountered, the species’ location should be reported to the Maryland DNR Natural Heritage Program.

You can also contact the Norton-Brown Herbarium ( for confirmation and we will relay the information to MD DNR.

Weakley, A. S. (November 2012, Draft). Flora of the Southern and Mid-Atlantic States. 1225 pp.

Weakley, A. S., J. C. Ludwig, J. F. Townsend (2012) Flora of Virginia. Crowder, B. (Ed.). Foundation of the Flora of Virginia Project Inc., Richmond. Fort Worth: Botanical Research Institute of Texas Press. 1554 pp.

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January 2015

Symphyotrichum novae-angliae (L.) G. L. Nesom

Common Name: New England aster

Family: Asteraceae

Identification: New England aster has dense clusters of purple heads with yellow centers. The involucre and peduncle of the inflorescence is densely glandular.The lower parts of the plant are often hairy. The leaves are mostly along the stems (cauline) and the leaf bases clasp the stem. Under ideal conditions, plants can be quite robust, reaching almost two meters tall and nearly a meter wide.

Ecology: New England aster is common along roadsides and the edges of fields and lawns. It flowers profusely from August until frost in Maryland.

Distribution:Native throughout North America north of Florida, Louisiana and Texas into the southern portions of most Canadian provinces. New England Aster is common in Maryland west of the Chesapeake Bay.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of New England aster, go to the:
Maryland Biodiversity New England Aster Species Page.

Broader interest: New England aster is often planted in native gardens. Its flowers provide late-season pollen and nectar for bees and butterflies.

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November 2014

Conoclinium coelestinum (L.) DC.

Common Name: Blue mistflower

Family: Asteraceae

Identification: The blue mistflower can be recognized by its corymb of blue (to purple), aster-like heads. The center of each head contains purple florets (as opposed to the yellow florets found in so many purple aster-like flowers). The plants form small clumps of frequently-branched stems reaching about 1 meter tall. Leaves are often opposite near the flowering heads although they may be subopposite or alternate lower on the plant.

Ecology: Blue mistflower is infrequent along the edges of roads and fields, but it is widespread throughout Maryland and the East Coast. It flowers from August until frost in Maryland.

Distribution:Native along the East Coast from New York to Florida. West to Michigan, Nebraska and Texas. Although native throughout this area, this species is also cultivated.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of blue mistflower, go to:

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October 2014

Asimina triloba (L.) Dunal

Common Name: Pawpaw

Family: Annonaceae

Identification: Pawpaw is a fairly recognizable species, even when fruits and flowers are lacking. The trees are generally part of the understory (up to 10 meters tall) and tend to grow in colonies. The leaves are large (up to a foot in length) and oblong. The fruit is of irregular shape – ovoid to kidney-shaped. The green fruits may be solitary or in small groups. The flowers are dark purple to brown with fleshy petals.

Ecology: The pawpaw tree is fairly common along the East Coast, preferring damp woods. The fruit of the pawpaw tree is edible and has a rich banana-like flavor when ripe.

Distribution:Native along the East Coast from Ontario to Florida. West to Minnesota, Nebraska and Texas.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of pawpaw, go to:

Trivia: You’re not likely to find pawpaw fruits in your local grocery store, but the fruits are eaten throughout their range. As the fruit becomes more popular, the fruits are turning up at festivals and farmers markets. One of the largest festivals dedicated to this spectacular fruit is the Ohio Pawpaw Festival, which has been held since 1998.

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September 2014

Rhexia virginica L.

Common Name: Virginia Meadow Beauty

Family: Melastromataceae

Identification: Rhexia virginica is a one to three foot tall perennial wildflower with 4 showy pink- purple petals and bright yellow stamens on its terminal flowers. The stem is light to purplish green and sharply four-angled. The simple, ovate leaves are in opposite pairs along the stem. All parts of the plant may be sparsely covered in bristles, especially the areas around the stem nodes and the floral tube.

Ecology: Rhexia virginica is a perennial species found in areas with moist and often acidic soil such as bogs, pond edges, ditches, and wet clearings .

Distribution: This species is common on the Coastal Plain, but can be found throughout the eastern half of North America.

Image courtesy of the USDA Natural Resources Conservation Service

Trivia: The firmly held pollen on Rhexia virginica's stamens can be easily dislodged by bees vibrating on the flower at a resonant frequency. This technique is known as ‘Buzz Pollination’.

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August 2014

Euastrum oblongum (Greville) Ralfs

Family: Desmidiaceae

Identification: Euastrum oblongum is a common microalga in the family Desmidiaceae. It is a member of a larger group (an order) commonly known as ‘desmids.’ Euastrum oblongum has the characteristic desmid organization of being unicellular with two halves (semicells) connected across a narrow bridge (the isthmus). The cell nucleus can be found in the center of the cell and a single, large chloroplast in each half of the cell. Euastrum oblongum is distinguished from other desmids by the shape of the cell and the characteristics of the lobes and cell surface.

Ecology: Euastrum oblongum is a strictly freshwater species that can be found among the benthic algae and metaphyton of many lakes and shallow wetlands. Most desmids are sensitive to nutrient pollution and Euastrum oblongum is no exception: it will generally not be found in nutrient-rich waters.

Distribution: This species is widely distributed in North America (Prescott 1977; Hall unpub.), including Maryland.

Prescott, G.W., H.T. Croasdale, and W.C. Vinyard, A Synopsis of North American Desmids Pt. II Desmidaceae: Placodermae sec. 2. 1977, Lincoln: University of Nebraska Press. 413.

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July 2014

Drosera intermedia Hayne

Common Name: Spatula-leaved Sundew

Family: Droseraceae (Sundew Family)

Identification: The species of sundew (Drosera spp.) that occur in Maryland are small (less than 10 cm tall), but the unique, glandular leaves (tentacles) are unmistakable. The leaves are arranged as a rosette and the flower stalks extend high above the plant. Within Maryland, wild species of Drosera can be distinguished based on the shapes of their leaves. In the case of D. intermedia, the spatula-shaped leaf is sufficient for identification.

Ecology: Drosera intermedia is a perennial plant that lives in damp, boggy areas. All sundews (Drosera spp.) are carnivorous flowering plants. They photosynthesize sugars, but also get nutrients by trapping insects on the glandular leaves. The sticky glands attract and trap insects that are then digested by enzymes.

Distribution: The species is infrequent, but fairly widely distributed in Maryland and along the East Coast. The species is native to Europe and North America and northern South America.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of Drosera intermedia, go to: Maryland Biodiversity Project Drosera intermedia checklist.

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June 2014

Sisyrinchium angustifolium Mill.

Common Name: Blue-eyed grass

Family: Iridaceae (Iris Family)

Identification: Blue-eyed grass is relatively easy to identify based on the combination of grass-like foliage and the blue to purple tepals terminated in a sharp tip. The different species of Sisyrinchium are differentiated based on the size of the plant, branching of the stems and the width of the stem.

Ecology: This species grows in damp open areas of meadows and woodlands. It can sometimes be encountered at the edge of cultivated fields or along roads and trails. In Maryland, it flowers from spring until early summer. Cultivars of S. Angustifolium are now generally available in Maryland through retailers carrying native plants.

Distribution: Native along the East Coast from the Arctic to Florida. West to Minnesota and Texas.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of Sisyrinchium angustifolium, go to: Maryland Biodiversity Project Sisyrinchium angustifolium checklist.

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May 2014

Sanguinaria canadensis L.

Common Name: Bloodroot

Family: Papaveraceae (Poppy Family)

Identification: These large (3-5 cm), solitary flowers can be found in from late March through May in Maryland. The flower grows low to the ground, just a few centimeters above the leaf litter. The petals are white and vary in number from 8-12. The conspicuous reproductive organs are a bright yellow. The flower is typically accompanied by a single multi-lobed leaf and often blooms before the leaf is fully open. The plant gets its name from the poisonous orange to red sap that is found throughout the plant.

Ecology: Sanguinaria canadensis grows in woodlands in both damp and dry soils. It typically blooms in the early spring before the tree canopy has developed and goes dormant again towards the middle of summer. The plants produce seeds with a nutrient-rich structure called an elaiosome. Ants collect the seeds and take them to their nests to feed the nutrients from the elaiosome to the larvae, effectively planting the seeds!

Distribution: Native all along the East Coast and west to the Dakotas and Texas.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of Sanguinaria canadensis, go to the Maryland Biodiversity Project Sanguinaria canadensis checklist.

Trivia: The reddish sap in the roots is a popular natural dye for use in Native American art. The sap was also approved by the FDA for use in toothpastes as an antibacterial agent, though it has recently been associated with the development of premalignant oral lesions.

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April 2014

Lygodium palmatum (Bernh.) Sw.

Common Name: American climbing fern

Family: Lygodiaceae

Identification:This species is easily identified, although often hard to find! Lygodium palmatum is unique among ferns in Maryland in that the fronds are twining. Each vine is a frond and the leaves are paired pinnules. Each pinnule has 3-7 palmately arranged lobes.

Ecology: The species prefers acid soils and requires near constant moisture. Although the plants die back, some fronds overwinter in Maryland. The genus Lygodium is more common and species-rich in the Tropics than in temperate North America.

Distribution: Native along the East Coast, New Hampshire to Florida and west to the Mississippi. The species is widely distributed on the East Coast but infrequent. Consequently, it is listed as threatened or endangered in several states, including Maryland. If you see this plant, please, take only pictures.

Image courtesy of the USDA Natural Resources Conservation Service

For county records of Lygodium palmatum, go to the Maryland Biodiversity Project fern checklist.

Trivia:The first plant-protection law in the US was written to ban the picking of Lygodium palmatum in Connecticut, where the fronds were once gathered for Christmas decorations.

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March 2014

Juniperus virginiana L.

Common Name: Eastern red-cedar

Family: Cupressaceae, redwood or cypress family

Identification:The species is easily identified by its blue to black berry-like cones and tightly appressed scaly needles.

Ecology: Common in early successional communities. Can be found in either moist or dry habitats, though perhaps more common in dry upland communities. This evergreen is conspicuous in winter whenever other vegetation has died back..

Distribution: Native along the east coast, Maine to Florida and west to the Dakotas, Colorado and Texas.

Image courtesy of the USDA Natural Resources Conservation Service

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February 2014

Rhus glabra L.

Common Name: Smooth sumac

Family: Anacardiaceae, cashew family

Identification: In winter, species of Rhus are easily recognized by their sparse branching and bright red fruits. Rhus glabra can be distinguished from other regional species of Rhus by its horseshoe-shaped leaf scars and the smooth (glabrous) twigs.

Ecology: Grows in open areas, often seen along highways or at the edges of fields.

Distribution: Common throughout Maryland and much of the United States.

Image courtesy of the USDA Natural Resources Conservation Service

Trivia: The word sumac traces its etymology from Old French sumac (13th century), from Mediaeval Latin sumach, and from Arabic and Syriac summāq - meaning "red".

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June 2013

Securigera varia (L.) Lassen

Common Name: crown vetch.

Family: Fabaceae Lindl. – bean/pea/legume family

Identification: summer – The individual flowers group into an umbel where all flower stalks, which are of approximately equal length, originate from one point on the inflorescence axis (peduncle). The banner (upper portion) of each flower has a darker pink hue than the keel (lower portion). Once the flowers are pollinated, fruits develop which resemble green beans. Each compound leaf is made up of an odd number of smaller leaflets.

Ecology: grows in disturbed areas such as road banks.

Distribution: Native range: Mediterranean Basin, common exotic in North America.

Image courtesy of the USDA Natural Resources Conservation Service

Trivia: commonly used for erosion control, green fertilizer, and fodder.

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May 2013

Erodium cicutarium (L.) L'Hér. ex Aiton

Common Name: redstem stork’s bill, heron’s bill, red-stem filaree.

Family: Geraniaceae Juss. – geranium family.

Identification: Spring – The whole plant is covered in conspicuous, soft hairs. Leaves are dissected and compound. The plants sport dainty, pink flowers from early spring – mid summer. Fruits resemble the long slender bill of a stork and twist like a corkscrew as they mature and break apart. Each section (awn) is attached to one seed.

Ecology: Grows in sandy, open areas or mixed in with grasses.

Distribution: Native range: Mediterranean basin, common exotic in North America.
Image courtesy of the USDA Natural Resources Conservation Service

Trivia: The seeds are brought underground by harvester ants or by self burying; the awns can warp and unwind during humidity fluctuations, effectively drilling themselves into the soil.

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April 2013

Liquidambar styraciflua L.

Common Name: Sweet gum.

Family: Altingiaceae Horan. – sweet gum family.

Identification: Winter – trees with grey, smooth and vertically fissured (in young trees) or deeply furrowed bark. The branches often have curious wing-like, corky outgrowths although the tips (last year’s growth) are smooth, glossy and a reddish-brown color. The unique fruits resemble a morning-star (weapon).

Ecology: Tolerant of different soil types (used as street tree), but prefers moist, humus-rich sites..

Distribution: Common in the mountains.
Image courtesy of the USDA Natural Resources Conservation Service

Trivia: The fragrant resin has been used as chewing gum, incense and for folk remedies.

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March 2013

Kalmia latifolia L.

Common Name: Mountain laurel.

Family: Ericaceae Juss. – blueberry or heath family.

Identification: Winter – Shrubs or small, gnarled trees with flaking bark and broad, glossy, leathery, evergreen leaves with an elliptic shape. The capsules have long stems, are covered in stalked glands, and split open to reveal five compartments, which release winged seeds. Terminal winter buds are slender and branched vs. egg-shaped, unbranched and covered by scales in species of Rhododendron.

Ecology: found in openings or edges of woodlands with acidic soil or covering entire mountainsides.

Distribution: Common in the mountains.
Image courtesy of the USDA Natural Resources Conservation Service

Trivia: This species forms symbioses with fungi, as do many Ericaceae.

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February 2013

Asclepias syriaca L.


Common Name: Common milkweed.

Family: Apocynaceae Juss. – dogbane family.

Identification: winter – Note the warty follicles (seed container), which split open along one side of their length to release seeds with long, fluffy tufts of hairs (coma). The seeds disperse by sailing away on wind currents. The follicles are “bird-shaped” with a pointy top (apex) and rounded base. Only a few flowers form follicles while the others drop off and leave a scar on the knobbly structure where the individual flower stalks were attached.

Ecology: disturbed areas such as roadsides and open fields, meadows..

Image courtesy of the USDA Natural Resources Conservation Service

Trivia: The flowers are fragrant and attract many pollinators.

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January 2013

Ludwigia alternifolia L.


Common Name: seedbox, rattlebox.

Family: Onagraceae Juss. – evening-primrose family.

Identification: winter – stems erect and branched. Note the striking stalked (pedicelled) cubic capsules with a pore for seed release up top (apical). The angles of the cube are winged (minutely so). The capsules are four-chambered and contain many seeds.

Ecology: wet, swampy habitats, pond edges, salt marsh.

Distribution: native range: eastern North America, common.

Trivia: the specific epithet, Latin: ‘alternifolia’ refers to the leaf arrangement on the stem, which is alternate.