Scientific Name: Urochloa platyphylla

Common Name: broadleaf signalgrass

Synonyms: Brachiaria extensa, Brachiaria platyphylla, Paspalum platyphyllum

Habit: A spreading summer annual, reaching a height of approximately 3 ft, that commonly is found growing along the ground but with tips ascending (decumbent growth habit). Roots are fibrous and capable of rooting at the lower stem nodes.

Leaves: Leaf blades are overall short and wide in appearance, approximately 1 1/2 to 6 inches long and 6-15 mm wide. Leaf blades are widest near the base and taper to the apex. Leaves are rolled in the bud and without hairs on either leaf surface except on margins and in the collar region. The ligule is a narrow membrane fringed with hairs, 1/2 to 1 mm long. Leaf sheaths are hairy. Leaves may have a crinkle on one side of the leaf blade while the other is smooth.

Identifying Characteristics: The relatively broad and short leaves of this grass weed make it easily distinguishable from other grasses. Additionally, the lack of hairs on the leaf blades, rooting stem nodes, and flattened spikelets help to identify broadleaf signalgrass from most other grasses found in similar environments. Stems of broadleaf signal grass are prostrate, branching and bent at the nodes. These plants often root at the lower stem nodes, and therefore are most commonly seen growing along the ground with some tips ascending (decumbent). Seedlings will often have leaf sheaths that are maroon-tinged and hairy throughout. Leaf blades are without hairs, except for those that occur on the margins. Leaf blades may also be maroon-tinged, with a fringed membranous ligule. Broadleaf signalgrass is similar to Texas panicum (<a href='../../weedimg/601'>Urochloa texana</a>) in growth habit and appearance. However, the leaves of broadleaf signalgrass are not covered with short, soft hairs like those of Texas panicum.

Flower Seed Head: Seedhead a raceme, approximately 12 inches long and 4 inches wide. Each seedhead has 2 to 6 'branches', approximately 1 to 3 1/2 inches long. Spikelets on the seedhead are somewhat flattened in appearance.

Seed Fruit: Seed are light brown in color and are approximately 3-4mm in length.

Where Found: Broadleaf signalgrass height is found most commonly as a weed of agronomic crops of the southeastern and south-central United States.

  • Life cycle: summer annual

  • Plant type: Grass

  • Auricle: not present

  • Plant family: Poaceae

  • Leaf arrangement: rolled in bud

  • Hair surface: hairs on basal half only; no hairs

  • Ligule: hairy; membrane

  • Length: 1-2 mm; less than 1 mm

  • Root structure: fibrous

  • Seed head: spike

  • Width: 6 to 15 mm

  • Grass stem: flat or oval