Eastern Forest Threat Center - Jointhead Grass

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Jointhead grass

Jointhead grass

Leslie Mehrhoff, University of Connecticut, Bugwood.org

Jointhead Grass
Arthraxon hispidus

Jointhead grass is native to China, Japan, and Korea. It often occurs with another highly invasive annual grass species, Japanese stiltgrass (Microstegium vimineum).

Keywords: Poaceae, annual, grass, creeping, hairy leaf margins, water-dispersed seeds, sunny moist habitats; Common names: hairy jointgrass, small carpgrass

Distribution Map Distribution Source Image

Threat Description

Jointhead grass is a low-growing creeping annual grass that grows to a height of 1 ½ ft. The ovate to lanceolate leaf blades are ¾ - 2 ¾ in. in length and 1/5 – 3/5 in. in width with hairs along the margins of the leaf blades. Heart-shaped (cordate) bases of the leaves encircle the sheath. Flowers appear from September to October. The individual flowers, or spikelets, are arranged in multiple spike-like racemes, averaging about 1 ½ in. long, that terminate the stems. The stems develop roots at the lower nodes. Seeds are slender and yellowish in color, measuring 1/6 in. long. Jointhead grass reproduces by seeds that can be dispersed by moving water. It favors sunny moist habitats and is often found in moist pastures and fields, shaded upland woods, floodplain forests, stream banks, and along shorelines, roads, and trails where soils remain moist. It can form dense stands that may threaten native vegetation, particularly along shorelines.