Scientific Name: Scleranthus annuus

Common Name: knawel

Other Common Names: german knotgrass, german moss

Habit: Usually a winter annual but occasionally a summer annual that forms dense, prostrate mats. Knawel is commonly mistaken as a grass and is primarily a weed of lawns, turfgrass, and small grains.

Leaves: Cotyledons are linear in outline and less than 1 mm wide with a sharp tip. This leads to their confusion with grasses. Leaves are linear in outline, less than 1 mm wide, also with a sharp tip. Leaves are arranged oppositely along the stem and joined by a thin, clear membrane. Stems grow prostrate along the ground, branched, forming dense mats outward from a central plant.

Identifying Characteristics: Plants with small, linear leaves that initially resemble a grass and inconspicuous green flowers. Due to the overall growth habit and leaf shape, this weed might be confused with Creeping Phlox (Phlox subulata), but the leaves and stems of German moss are not covered in hairs like those of creeping phlox. German moss might also be confused with some of the spurries (Spergula spp.) but lacks the distinctive white or red flowers of these species.

Flower Seed Head: Flowers are inconspicuous, green in color, and somewhat spiny. Flowers occur in clusters that arise from the position between the leaf bases and the stem.

Seed Fruit: A very small (3-4 mm) utricle.

Where Found: Knawel is distributed throughout the eastern United States.

  • Life cycle: winter annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Caryophyllaceae

  • Leaf arrangement: opposite

  • Leaf shape: lance; needle

  • Ochrea: Present

  • Leaf margin: entire

  • Stem hairs: no hairs; has hairs

  • Flower color: green

  • Growth habit: prostrate and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: has hairs

  • Flower diameter: pencil

  • Flower symmetry: radial symetery

  • Root structure: fibrous

  • Leaf stalk: none