Schoenus riparius

Schoenus riparius is a robust species having relatively long and wide panicles compared to other closely related species.^[1] This species has aristate spikelets.^[1]

One of the species that most closely resembles S. riparius is Schoenus loreus, but that species has flat non-channelled leaves compared to the channelled leaves that become terete above as in S. riparius.^[1]

A second species that resembles S. riparius is Schoenus australis, which is also a relatively large and robust species.^[1] Site preferences differ between these two species, however, as S. riparius occurs on damp sites on the Cape Peninsula, whereas S. australis is found on coarse-textured soils (e.g. sandy sites).^[1] In addition, the inflorescence of S. australis is shorter and thinner compared to that of S. riparius.^[1]

Schoenus crassus also resembles S. riparius, but the former species usually has firmer and stiffer basal leaves compared to the more lax leaves of S. riparius.^[1] Furthermore, S. riparius has darker reddish-brown culm bases, inflorescences and spikelets compared to S. crassus.^[1]

Similar to other sedges, plants in this group are very difficult to identify. It appears that part of this problem is caused by the tendency of the southern African Schoenus to form hybrids with each other.^[2] Due to a lack of evidence, it is unclear whether S. riparius forms hybrids with other southern African Schoenus species.^[1]