Agronomic Weeds - 2 CS 414 Weed Science Laboratory

Smallflower morningglory Jacquemontia tamnifolia Convolvulaceae Summer annual, light blue flowers in clusters. Rounded cotyledons, resemble mustard Hairs on leaf margins, sometimes on blade.

Red morningglory Ipomoea coccinea Convolvulaceae Hairless, maroon hypocotyls. Cotyledons somewhat lobed, rounded points, tinted maroon, especially around margins. Leaves with “points” along base of blade. Flowers dark red, long, tubular (color distinct). Fruit is a capsule (all MG).

Ivyleaf morningglory Ipomoea hederacea Convolvulaceae Cotyledons notched at apex, shallower notch than I. lacunosa. First true leaf is distinctly lobed, adult leaves have ivy-shape. Upright hairs along leaves, stems, petioles. Flowers blue to purple.

Entireleaf morningglory Ipomea hederacea var. integriuscula Convolvulaceae Heart-shaped leaves, hairy stand straight-up on leaf blade. Cotyledons have rounded points, moderately indented. Petals purple to pale blue, sometimes white, funnel-shaped or tubular flower.

Pitted morningglory Ipomoea lacunosa Convolvulaceae Cotyledons deeply lobed, forming a ‘V’, glabrous. Stems and leaves slightly hairy. Apex of leaves extended. Leaves appear outlined with maroon. White flowers.

Tall morningglory Ipomoea purpurea Convolvulaceae Moderate indention on cotyledons. Lobes are rounded. Cotyledons most “boxed” of all MG. First true leave and onward are heart-shaped. Leave bases over-lap at petiole-leaf connection (unlike I. lacunosa). Stems appressed on leaf blade. Purple flowers.

ladysthumb Polygonum persicaria Polygonaceae Elliptic cotyledons with hairs along margins. True leaves alternate, lanceolate. Blades may have a purple watermark (resembles a lady’s thumb print). Fibrous roots. Purple flower spike. Ocrea has stiff hairs unlike P. pensylvanicum.

Pennsylvania smartweed Polygonum pensylvanicum Polygonaceae Cotyledons and leaves similar to P. persicaria. NO hairs on ocrea. Stems are swollen at nodes and have reddish cast. Found in wet locations of fields.

Solanum carolinense horsenettle Solanaceae Perennial Stiff hairs on oblong cotyledons. Rhizomatous. Light purple flowers. Spines on leaf blade. All parts poisonous, except mature fruit. Light purple flowers. Fruit is a berry. Stems angled at nodes, extremely tough. Woody when older. Plant resembles cultivated eggplant.

Wild radish Raphanus raphanistratum Brassicaceae Winter annual. May germinate in spring or early summer. Heart-shaped cotyledons. First true leaves are hairy & lobed. Toothed margins on all leaves. Stiff hairs on all leaves. Plant grows as basal rosette. Fruit is a silique (resembles a pod, but with central partition). Yellow flowers on hairy stems.

Carolina geranium Geranium carolinianum Geraninaceae Biennial or winter or summer annual. Cotyledons hairy, kidney shaped. Basal rosette until upright stems and flowers develop. Stems to 28”, pink to red with dense hairs. Leaves hairy on upper and lower blade. Deeply divided with lobes on each division. Flowers light pink to purple, clustered at end of stems. Fruit resembles a crane’s bill.

Leaves rolled in the bud (i.e. smooth crabgrass) Leaves folded in the bud (i.e. goosegrass)

Common Name: broadleaf signalgrass Family: Poaceae Genus: Brachiaria Species: platyphylla summer annual no hairs on leaf blades except margins leaf sheaths hairy, often maroon ligule is a narrow membrane fringed with hairs rooting stem nodes short blades stick out from stem

Common Name: crowfoot grass Family: Poaceae Genus: Dactyloctenium Species: aegyptium annual Hairs extend outward from the margins at even spacing, rest of the plant usually hairless Seedhead resembles a crow’s foot Ligule is fringed, membranous at base

Common Name: barnyardgrass Family: Poaceae Genus: Echinochloa Species: crus-galli Summer annual No ligule Leaf blades glabrous, may have a few hairs at the base White midvein on leaf blades

Italian ryegrass Lolium multiflorum Poaceae Winter annual to 3 ft. Weed of small grains. Leaf sheaths are tinged red at base. Rolled vernation. Claw-like auricles at collar. Membranous ligule. Lower leaf blade glossy. Flower is a spike with alternately arranged awns.

Common Name: fall panicum Family: Poaceae Genus: Panicum Species: dichotomiflorum Summer annual stem will bend at the nodes = zig-zag growth pattern ligule is a fringe of hairs often fused at the base prominent white midvein on leaf blades hairs on lower surface of leaf blades as seedling, glabrous when mature

Texas panicum Panicum texanum Poaceae Spreading summer annual. Soft hairs on sheaths and blades. Membranous ligule with fringe of hairs. Seedhead a narrow panicle. May root at lower stem nodes.

Common Name: giant foxtail Family: Poaceae Genus: Setaria Species: faberi Summer annual upper surface of leaves covered in short hairs, except at the base ligule fringe of hairs seedhead larger than green or yellow foxtail, and droops when mature

Common Name: yellow foxtail Family: Poaceae Genus: Setaria Species: glauca Summer annual long, silky hairs near leaf base only (distinguish from giant and green) ligule is a fringe of hairs Seedhead yellow

Common Name: green foxtail Family: Poaceae Genus: Setaria Species: viridis Summer annual leaves have no hairs ligule is a fringe of hairs seedhead greenish

Common Name: shattercane Family: Poaceae Genus: Sorghum Species: bicolor Summer annual Leaf blades wider and longer than johnsongrass when mature No rhizomes, does tiller Large, membranous ligule

Common Name: johnsongrass Family: Poaceae Genus: Sorghum Species: halepense perennial has rhizomes very large, membranous ligule leaf blades mostly glabrous, a few hairs may appear near the base prominent white midvein on blades may reach 6.5 feet tall!