Mulligan (Agriculture Canada, Ottawa, retired)
Acalypha virginica L. var. rhomboidea (Raf.) Cooperr., three-seeded mercury, ricinelle rhomboïde
An annual herb hat reproduces only by seed. It has erect, usually single, stems from 3 to 40 inches (7.5 to 100 cm.) tall. It occurs in the southern part of Nova Scotia, Quebec, and Ontario, and in the eastern and central United States. It is a native in moist soils of river flats and in the borders and openings of woods. It is naturalized as a weed in cultivated fields, ditches, roadsides and waste places. Young plants resemble both redroot pigweed and green pigweed, Amaranthus species (see photos under Amaranthaceae-amaranth family). Three-seeded mercury can be distinguished from both pigweeds by its glossy leaves, toothed leaf margins and the clusters of green flowers, with lobed bracts, in the axils of leaves.
Euphorbia cyparissias L., cypress spurge, euphorbe cyprès
Perennial, with underground rootstocks; most patches are
sterile, and are very small, isolated, and spreading slowly; a
few infestations, composed of fertile plants that set seed,
become quite extensive; stems up to 1 foot (3 dm.) high;
flowering inflorescences yellow; throughout most of our range,
but most common in southeastern Quebec, southern Ontario, and
southward into the eastern United States; roadsides, waste
places, pastures, and open woods; often an escape from older
cemeteries; introduced from Europe as an ornamental.
Euphorbia esula L., leafy spurge, euphorbe ésule
Perennial, spreading mainly by its persistent, vertical and
horizontal underground roots, and much less by seed; stems
erect, from 1 to 3 feet (3 to 9 dm.) high; flowering
inflorescences from green to yellow; locally common throughout
most of our area, particularly the mid-west; widespread, often
very localized; a serious weed in native prairie and rangeland
in the mid-west; grain fields, meadows, pastures, prairie,
rangeland, roadsides, and waste places; introduced from Europe
The milky juice of both of these spurges can cause a dermatitis
in humans. Photosensitization, causing poisoning and death has
occurred in animals after eating these spurges. However, most
poisoning occurs when animals eat contaminated hay. Grazing
animals usually avoid plants growing in the field.
Euphorbia vermiculata Raf., [= Chamaesyce vermiculata (Raf.) House], hairy-stemmed spurge, euphorbe vermiculée Hairy-stemmed spurge is an annual herb with prostrate to semi-erect, sparsely pilose, stems. Its leaves are ovate to lanceolate, serrulate, and pilose on the lower surfaces. Capsules are glabrous, and are 1.5 to 2.0 mm long. Seeds have transverse wrinkles and are also 1.0 to 1.5 mm long. It is a native plant on sandy, gravelly and rocky shores of lakes and rivers, and is a weedy colonizer along roadsides and railway lines and in trampled areas around human habitation. It occurs in southeastern Canada, Vancouver Island in B.C., and in the northeastern United States, Arizona and New Mexico. It has a chromosome number of 2n= 16. Several other superficially similar annual prostrate spurges occur in our area.