Juncus brachycarpus is a perennial rush 30-80 cm tall, stems from along a stout white, rhizome.
Leaves usually 2, round, internally partitioned.
Flower heads round, 2-10, 0.7-1 cm wide, densely flowered, bristly, flowers dull brown to pale green, sepals 0.3-0.4 cm slightly longer than petals, both narrowly lance-shaped, stamens 3, shorter than sepals; inflorescence branched, longer than bract leaf below it.
Fruit capsule 3-sided, tip pointed, much shorter than petals or sepals, internal partitions incomplete, June-Sept.
Wetland status: FACW.
Frequency in NYC: Very infrequent (NYS endangered (USDA, NRCS 2010).
Habitat: Bogs, wet soil, soil pH 4.5-6.7 moderately tolerant of shade (USDA, NRCS 2010).