Use the photos below to identify weeds
in the field. Names link to more on
identification and biology.
Click on photos to enlarge
(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.
(Chamomilla suaveolens): Sunflower family; summer
or winter annual; seed leaves narrowly oblong to linear, fused at base,
pointed or rounded at the tip; first true leaves opposite, smooth-edged
or with feather-like lobes; later leaves alternate, with feather-like
lobes, forming a rosette.
(Sonchus oleraceus): Sunflower family; summer or winter annual; seed leaves
markedly stalked, almost spoon-shaped, rounded at tip and often have grayish
powdery bloom; injured tissue bleeds milky white latex.
(Melilotus sp.): Pea family; biennial, sometimes annual or short-lived
perennial; seed leaves oblong, smooth; first true leaf oval, narrow at
base and squared at tip with a minute nipplelike point; subsequent leaves
compound with three leaflets, each resembling the first true leaf.
(Chenopodium murale): Goosefoot family; summer
annual; seed leaves oblong to narrowly lance shaped, dark green;
true leaves weakly toothed, leaf surfaces, especially lower surface,
sparsely covered with tiny dotlike scales.
(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 translucent granules.
(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 their
(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.
(Portulaca oleracea): Purslane family; summer annual; seed leaves oblong,
somewhat club shaped, succulent, maroon on lower surface, and green or maroon
on upper surface; young leaves smooth, succulent, oblong, green on upper surface,
maroonish underneath, and broadest around leaf tip, with short petioles.
(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.
(Euphorbia maculata(=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.
(Echinochloa crus-galli) Grass family; summer annual;
first leaf dull gray green; stem flattened, purplish; no ligule.