Thamnochortus pluristachyus is a tufted restio growing unbranched culms from rhizomes to heights of 1 m to 1,5 m. The tussocks become about 1 m in diameter.
The culms are covered in tight, persistent sheaths growing from the nodes. The sheaths are frayed in their top halves.
Many pendulous male spikelets grow on one culm. The brown spikelets are oblong with pointed bracts longer than the florets. The spikelets are compressed, each consisting of six segments, the outer segment boat-shaped.
The species, a Western Cape endemic, is distributed coastally from Bredasdorp to Stilbaai, mainly on the Agulhas Plain.
The habitat is limestone fynbos. The species population is decreasing, hampered by invasive species, but enjoys protection in the De Hoop Nature Reserve. It is considered to be vulnerable in its habitat early in the twenty first century (Leistner, (Ed.), 2000; Bond and Goldblatt, 1984; http://redlist.sanbi.org).