Weeds, Summer Annual

Use the photos below to identify weeds in the field. Names link to more information on identification and biology.

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Barnyardgrass (Echinochloa crus-galli): Grass family; summer annual; first leaf dull gray green; stem flattened, purplish; no ligule.	Common cocklebur (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.	Common lambsquarters (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.
Common purslane (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.	Crabgrass (Digitaria spp.): Grass family; summer annual; stems branch at base, are flattened in cross-section, and grow upright or prostrate; leaves are flat, rolled in the bud and have a prominent midvein; sheaths are open and flattened.	Foxtails (Setaria spp.): Grass family; summer annual; first leaves are usually parallel to the ground; grow in loose clumps or singly; stems are erect or bent at the base, but overall ascend upward; mature leaves are long and most have a spiral twist.
Hairy fleabane (Conyza bonariensis): Sunflower family; summer annual; seed leaves gray green; first leaves narrow and covered with short, soft hairs; often wrinkled or distorted.	Horseweed (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.	Ladysthumb (Polygonum persicaria): Buckwheat family; summer annual; cotyledons are wide, dull green, oblong, with short hairs on the edges near the base, and have short stalks that are fused at the base.
Morningglories (Ipomoea spp.): Morningglory family; summer annual; seed leaves deeply notched; heart-shaped first true leaves with deep lobes at base; stem below seed leaves maroon at base and green toward leaf tip.	Mustards (Brassica spp.): Mustard family; winter or summer annual or biennial; cotyledons are kidney shaped, broader than long, hairless, and have a deep notch at tip; stalks are longer than the cotyledon blade; first true leaves are bright green on upper surface and paler below.	Pigweeds (Amaranthus spp.): Pigweed family; summer annual; seed leaves long and narrow with red undersides; first true leaves have notched tips and much broader than seed leaves.
Russian thistle (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 length.	Sprangletops (Leptochloa fascicularis): Grass family; summer annual; leaves on seedlings are light green usually with a white midrib.	Sweetclover (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.
Common knotweed (Polygonum arenastrum): Seed leaves are long, very narrow, rounded at the tip and light green with a white cast. The true leaves are much broader, emerging from an encircling, membranous sheath at the leaf base.