Names link to more information on identification and biology.
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(Urtica urens): Nettle family; winter or summer annual;
rounded seed leaves with smooth margin and small notch at tip;
first true leaves with small notch at tip, opposite, stalked,
and distinctly toothed.
(Senecio vulgaris): Sunflower family; winter annual, but seedlings can
be present anytime at cool, moist locations; seed leaves narrow, with blunt narrow
tip; first true leaves with shallow teeth; third and fourth leaves more deeply
(Xanthium strumarium): Sunflower family; summer annual;
seed leaves bright green, shiny on upper surface, pointed, and
about 6 times longer than wide; true leaves on seedlings notched
on margins and taper to leaf tip; bur may remain attached to
base of seedling.
(Conyza bonariensis): Sunflower family; summer annual;
seed leaves gray green; first leaves narrow and covered with
short, soft hairs; often wrinkled or distorted.
(Conyza canadensis): Sunflower family; summer annual;
seed leaves dull green, oval with fine hairs, and with short
stalks that sometimes may be tinged brown purple; first
true leaves covered with hairs on upper surface and margins;
undersides of early leaves smooth.
(Gnaphalium purpureum): Sunflower family; winter annual, summer annual,
or biennial; seed leaves and first true leaves covered on both sides with whitish
hairs; seed leaves 2 to 3 times longer than wide.
(Physalis spp.): Nightshade family; summer annual or perennial; seed
leaves yellow green to gray green; first leaves oval to triangular,
with smooth or slightly wavy margins, and a strong odor when
(Solanum nigrum): Nightshade family; summer annual or
short-lived perennial; seed leaves oval and pointed; first
true leaves spade shaped with smooth edges; lower surfaces
often purple; petioles stems and leaves with some hairs.
(Solanum physalifolium=Solanum sarrachoides): Nightshade family; summer annual;
seed leaves narrow, small, and lance shaped with very short
soft hairs along edges; first true leaves with wavy edges
and prominent veins.
(Amaranthus blitoides): Pigweed family; summer annual;
seed leaves narrow, pointed, 6 to 8 times longer than wide,
with magenta undersides; first true leaves broader, with shiny
upper surface and usually magenta-tinged undersides; edges somewhat
(Amaranthus retroflexus): Pigweed family; summer annual;
seed leaves long and narrow with red undersides; first true
leaves with notched tips and much broader than seed leaves.
(Amaranthus albus): Pigweed family; summer annual; seed
leaves 3 to 5 times longer than wide, bright green on surface,
magenta on underside; first true leaves spatulate, dark green
with wavy margins, red color underneath; midrib with notched
tip and bristle at end.
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(Croton (=Eremocarpus) setigerus): Spurge
family; summer annual; seed leaves oval; first true leaves
oval to heart-shaped; leaves covered with star-shaped hairs,
which give the plant a gray-green, mealy appearance.
(Euphorbia (=Chamaesyce) maculata): Spurge family;
summer annual; seed leaves oval, tips roundish, blue green
with smooth margin; first true leaves rounded, leaf surface
smooth and dull, dark green with reddish tinge.
(Polygonum arenastrum): Knotweed family; summer annual or short-lived
perennial with fall or spring seedlings; seed leaves are long,
very narrow, rounded at the tip and light green with a white
cast; true leaves are much broader, emerging from an encircling,
membranous sheath at the leaf base.
(Portulaca oleracea): Purslane family; summer annual;
seed leaves oblong, narrower at base or somewhat club shaped;
first true leaves smooth, oblong, broadest around leaf tip,
petioles short or absent; seed leaves and true leaves succulent,
dark purple or reddish on lower surface; upper surface green
or green and dark red to purplish.
(Chenopodium album): Goosefoot family; summer annual;
seed leaves are narrow, with nearly parallel sides; seed leaves
and early true leaves dull blue green above and often purple
below; young leaves have mealy appearance from coating of fine
(Salsola tragus): Goosefoot family; summer annual; cotyledons
and first true leaves long and thin; first leaves
are fleshy, soft, and weakly spine-tipped; stems slender
and flexible, often with reddish purple striations along
(Tribulus terrestris): Caltrop family; summer annual;
seed leaves thick, brittle, 2 to 3 times longer than wide;
petioles pinkish; true leaves dark green with grayish underside
and rough margins.
(Ipomoea spp.): Morningglory family; summer annuals or perennials;
seed leaves deeply notched; heart-shaped first true leaves with
deep lobes at base; stem below seed leaves maroon at base and green toward
(Oenothera laciniata): Evening primrose
family; summer annual, biennial, or short-lived perennial;
seed leaves ovate-elliptical; bases tapered to a stalk
on seed leaves and first true leaves; first true leaves
elliptical, alternate, with short veins that are often
Field bindweed (perennial)
(Convolvulus arvensis): Morningglory family; perennial,
with most new shoots and seedlings emerging in spring; seed
leaves nearly square, with shallow notch at tip; early true
leaves spade shaped; petioles flattened.