Scientific NameJuncus tenuis
Other Common Names:
Synonyms (former Scientific Names):
Juncus tenuis var. multicornis
Juncus tenuis var. williamsii
A grass-like plant that grows in clumps. Most growth occurs in summertime along with flower and seed production.
Seedling leaves are grass-like and have white auricles. Leaves arise at the base of plants and are flat on the ends but the margins roll inward until the leaf is almost round and hollow as it folds in on itself. Ligules are absent but auricles are papery like a ligule. The auricles are ear-like extensions.
Leaf-like bracts that extend beyond the flowering cluster and hollow stems.
Flower Seed Head
Flowers are borne on long stems that are round, hollow, wiry, and dark green. Flowers occur from June through August and are produced in clusters (cymes) near the ends of the stems. Two (up to 10 in long) leaf-like bracts often extend beyond the flower cluster. Flowers are small, greenish brown (2.8-5 mm long), with lanceolate sepals and petals (3 each).
Fruit are egg-shaped capsules (2.6-4.2 mm long) that split into 3 sections at maturity. Seeds are small (0.5 mm or smaller in length) and orange-brown.
Slender rush is a weed of turfgrass, landscapes, and nursery crops, especially along paths and in gravel or stone driveways and roads. It also grows in pastures, meadows, and waste places, on both moist and dry sites. It is particularly successful in compacted soils. It is native to all 50 states.
Leaf Hair on Upper Surface
rolled in bud
Mature Leaf Width
less than 5 mm