Galium trifidum is a perennial herb, slender, to 40 cm, much branched, matted, roughened by minute back-pointing hooks.
Leaves mostly in whorls of 4, linear, 1-2 cm long, tips blunt.
Flowers whitish, minute 3-parted, 0.1 cm wide, mostly solitary on stalks longer than 1 cm, from nodes; blooms and fruits July-Sept.
Fruit dry, round, 2-parted capsule, about 0.1 cm.
Wetland status: FACW+.
Frequency in NYC: Very infrequent.
Habitat: Open marshes, soil pH 4.6-8 (USDA, NRCS 2006).