Schoenus albovaginatus
Schoenus albovaginatus is a species of sedge endemic to the mountains of south-western South Africa. Description. The key diagnostic character of "S. albovaginatus" is its ivory-colored, membranaceous leaf sheaths. The inflorescence of "S. albovaginatus" is short and congested, appearing compressed between its lower primary inflorescence bracts. Another key morphological character of "S. albovaginatus" are its relatively long and numerous perianth bristles. Similar to "S. albovaginatus", "Schoenus aureus" and "Schoenus triticoides" also have ivory-colored, membranaceous, loose leaf sheaths; however, the inflorescence shapes of the latter two species differ from that of "S. albovaginatus". The lower inflorescence  bracts of "S. albovaginatus" do not have the marginal membranaceous extensions that are evident in "S. aureus" and "S. triticoides". In addition, the wheat-like panicle of "S. triticoides" is longer than the short, compressed inflorescence of "S. albovaginatus". Finally, neither "S. aureus" nor "S. triticoides" have the long perianth bristles that are present in the spikelets of "S. albovaginatus. The flowering heads of "S. albovaginatus" resemble those of "Schoenus pictus"; however, the latter species lacks the membranaceous leaf sheaths present in "S. albovaginatus". Plants in the southern African "Schoenus" clade are very difficult to identify, which is similar to  other sedges. It appears that part of this problem is caused by the tendency of the southern African "Schoenus" to form hybrids with each other. It is not clear whether "S. albovaginatus" forms hybrids with other southern African "Schoenus" species. Taxonomy. "Schoenus albovaginatus" is a species in family Cyperaceae, tribe Schoeneae. Other notable genera in tribe Schoeneae include "Lepidosperma", "Oreobolus", "Costularia", "Tetraria" and "Gahnia". The most closely related species to "S. albovaginatus" are other southern African "Schoenus" species, specifically, species in the "Schoenus compar" - "Schoenus pictus" and allies group. Southern African "Schoenus" were once classified as "Tetraria"; however, based on  molecular and morphological differences, we now know that the two groups are evolutionary distinct. To ensure that this group of sedges is monophyletic (i.e. the genus only has closely related species), several species of "Epischoenus" and the southern African "Tetraria" were transferred into "Schoenus". In the field, the southern African "Schoenus" can be distinguished from "Tetraria" species by their lack of stem leaves and the absence of reticulate sheaths at the bases of the flowering stems. Distribution and habitat. "Schoenus albovaginatus" has been observed growing in high mountain sites (> 900 m) in the southwestern mountains of South Africa, specifically  in the Koue Bokkeveld and Hex River Mountain areas. One collection has also been made in the area near Worcester.