prostrate spurge (Chamaesyce maculata)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMMON NAMES:
milk purslane
prostrate spurge
spotted sandmat
spotted spurge

 

SCIENTIFIC SYNONYMS:
Chamaesyce mathewsii Small
Chamaesyce supina (Raf.) H. Hara
Chamaesyce tracyi Small
Euphorbia maculata L.
Euphorbia supina Raf.

 

CONFIRMATION STATUS: Pending confirmation.

 

TAXONOMY: The currently accepted scientific name for prostate
spurge is Chamaesyce maculata (L.) Small. The taxonomy of the Ground
Spurges is rather confused. Some authorities assign them to the Euphorbia
Genus, rather than the Chamaesyce genus. Over the years, reassignment
of the names of species has been common. Other scientific names for pros-
trate spurge include Euphorbia supina and Chamaesyce supina. Some-
times Chamaesyce nutans (nodding spurge) is incorrectly referred to as
Chamaesyce maculata. Another problem is that the Ground Spurges are
similar in appearance and difficult to identify.

 

Three species of the Chamaesyce genus have been identified as occurring
in Facquier County: 1) prostrate sandmat (Chamaesyce prostrata (Ait.)
Small), 2) eyebane (Chamaesyce nutans (Lagasca y Segura), and 3)
prostate spurge (Chamaesyce maculata (L.) Small). Further research is
necessary to determine whether other members of this rather inconspic-

uous genus occur in Sky Meadows Park.

 

NATIVE STATUS: Native, United States; introduced, Canada.

 

GENERAL BOTANICAL CHARACTERISTICS:

 

Habit: Prostrate spurge is a native annual plant branches frequently at the

base, forming a spreading mat against barren ground that is about 6-18"

across, but usually less than 1" tall. However, where other vegetation is

present, the stems may ascend to 6" in height. The slender round stems are

more or less covered with hairs, and often turn pale red in the presence of

bright sunlight. Prostrate spurge grows close to the ground, often forming

a dense mat. The stems contain a milky sap. The short stems have a separ-

ate stipule - a very small scalelike appendage—at their base.

 

Leaves: The opposite dark green leaves are up to ¾" long and ¼" across,

but they are usually smaller in size. They are oblong in shape, smooth or

slightly toothed along the margins, and have short petioles. Each leaf is

more or less oblique at the base (i.e., asymmetrical where the petiole joins

the leaf blade), and it often has a red blotch near the middle (down its cen-

ter vein) on the upper surface. Like the stems, the leaves contain a milky

sap. Broken stems and branches readily secrete a milky, poisonous sap.

The sap is an eye and skin irritant.

 

Flowers: From the axils of the leaves, there often appears either a single

flower or, more commonly, a small leafy cluster of flowers. Like other Chamaesyce spp. (Ground Spurges), prostrate spurge is usually monoec-

ious, each plant having separate male and female flowers. Less commonly,

a plant may be unisexual, producing either all male flower or all female

flowers, but not both. Each male or female flower is less than 1/8" across,

and consists of a small floral bract in the shape of a cup (called cyathia),

which contains 4 glands with petal-like extensions along its upper edge.

These petal-like structures are either white or light red to pinkish and quite

small. Each cup-shaped bract has a slit on one side that is 1/4–1/3 as long

as the bract.

 

Fruit/Seeds: Each female flower has a 3-valved seed capsule, 1/16 inch

or less, that is hairy and hangs along the side of the bract from a stout

pedicel. Each valve of the capsule contains a single 4-angled seed, about

1/25 inch long, that is minutely pitted and has faint transverse ridges across

its surface. The seeds are hydrophilic and can adhere to surfaces when they

are wet. Each male flower has 4 stamens with yellow anthers that extend

beyond the rim of the cup-shaped bract. Neither female nor male flowers

have any petals or sepals. There is no noticeable floral scent.

 

Roots: The root system consists of a slender taproot. The taproot is often

long, capable of extending more than 24 inches into the soil, and is very

difficult to remove.

 

REGENERATION PROCESS: Prostrate spurge propogates itself by
reseeding. Its seeds become sticky when wet; they can cling to the fur of
animals and to the bottoms of shoes, spreading the seeds to sidewalks,
roads, and waste places.

 

HABITAT TYPES: Habitats include glades, dry sand prairies, cropland,
gravelly areas along railroads and roadsides, lawns and gardens, cracks in
sidewalks and pavement, borders along buildings, and sterile waste areas
containing sand, gravel, or compacted soil. This plant prefers disturbed
areas, and it is quite common in urban areas where there is a decaying
infrastructure.

 

SITE CHARACTERISTICS: Prostrate spurge prefers full sun, dry con-

ditions, and open barren ground that is sandy, gravelly, or rocky. Prostrate
spurge thrives in situations where radiated surface heat is higher than norm-

ally encountered. It can grow on top of sidewalks, curbs, cement, and as-

phalt roads and driveways where the surface temperature is higher than
conventional soils.

 

Most "weedy" spurges are summer annuals that don’t like competition and
depend on their prolific seed production for survival. A single plant can

produce several thousand seeds, which are small and can remain dormant

in the soil until conditions are suitable for germination. Seeds produced in
summer germinate immediately while those produced in late fall mostly
will lie dormant and won’t germinate until spring.

 

SEASONAL DEVELOPMENT: The blooming period occurs from mid-
summer through the fall and lasts about 2 months for individual plants.

 

GENERAL DISTRIBUTION: Prostrate spurge is found throughout the
continental United States. It is also found from Nova Scotia westward to
Ontario (except Newfoundland) and again in British Columbia.

 

SKY MEADOWS DISTRIBUTION: To be determined.

 

IMPORTANCE AND USES: Prostrate spurge's flower nectar attracts
small bees, flower flies, and wasps. Some upland gamebirds eat the seeds,
including the mourning dove and greater prairie chicken. The milky juice
of the foliage is somewhat toxic to mammalian herbivores, and so this

plant is rarely eaten by them.

 

Prostrate spurge can establish itself in horticultural, agricultural, and non-
crop sites. It overgrows sparse turf areas and low-growing ground covers,
invades open areas in gardens and landscapes, and can grow in sidewalk
cracks. In addition to reducing the growth of desirable plants, spotted
spurge reduces uniformity and quality of turf, provides a habitat for
undesirable insects in citrus groves, serves as an intermediate host for
fungal diseases of cultivated crops, and attracts ants with its seed.

 

Prostrate spurge is poisonous and can kill sheep grazing in pastures where
it is the predominant weed.

 

 

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