''Schoenus adnatus'' is a species of sedge endemic to mountainous locations in southern regions of South Africa.

Description

''Schoenus adnatus'' is a species of southern African '' Schoenus'' that shares traits characteristic of the ''Epischoenus'' group of ''Schoenus''. The main important character distinguishing ''S. adnatus'' from other similar species is that the spikelet

receptacle Receptacle may refer to: Biology * Receptacle (botany), a plant anatomical part * Seminal receptacle, a sperm storage site in some insects Electrical engineering * Automobile auxiliary power outlet, formerly known as ''cigarette lighter recep ...

adnate Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins – sometimes popularly referred to as Siamese twins – are ...

to the lowest (

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

) glume (

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

). The growth forms of '' Schoenus gracillimus'' and '' Schoenus schonlandii'' similar to that of ''S. adnatus''; however, neither of these two species have a spikelet receptacle that is adnate to the lowest glume. ''Schoenus adnatus'' can sometimes be slightly hairy, but its spikelets and culms are much less hairy that those of '' Schoenus crinitus''. Another difference between the two species is that the culms of the ''S. adnatus'' are narrower (≤ 5 mm) than those of ''S. crinitus'' (≥ 6mm). The southern African ''Schoenus'' tend to form hybrids with each other, which partially explains why they can be difficult to identify. It is impossible to determine if ''S. adnatus'' forms hybrids with other southern African ''Schoenus'' species because of a lack of evidence.

Taxonomy

''Schoenus adnatus'' is a species in family

Cyperaceae The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' w ...

, tribe Schoeneae. ''Costularia'', ''

Gahnia ''Gahnia'' (sawsedge, saw-sedge) is a genus of sedges native to China, Southeast Asia, New Guinea, Australia, New Zealand and a number of Pacific Islands. The common name is due to the toothed margins. It often forms tussocks. Species Accept ...

'', '' Lepidosperma'', ''

Oreobolus ''Oreobolus'' is a genus of flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel ...

'' and ''

Tetraria ''Tetraria'' is a genus of flowering plants in the sedge family, Cyperaceae, native to Tanzania, South Africa, Borneo, Australia and New Zealand. The type species is '' Tetraria compar'' (L.) P.Beauv. Recent molecular work has shown that ''Tetr ...

'' are other notable genera in tribe Schoeneae. Morphological evidence suggests that ''Schoenus adnatus'' is most closely related to other southern African ''Schoenus'' species, especially species in the ''Epischoenus'' group. The southern African ''Schoenus'' were previously included within the genus ''Tetraria''; however, we now know that the two groups are evolutionary distinct based on molecular and morphological differences. In 2017, several species of ''Epischoenus'' and the southern African ''

'' were transferred into ''Schoenus'' to ensure that this group of sedges is

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

(i.e. the genus only has closely related species). The southern African ''Schoenus'' can be distinguished from ''Tetraria'' species in the field by their lack of stem leaves and the absence of reticulate sheaths at the bases of the flowering stems. Few recent field collections of ''S. adnatus'' exist, meaning that it has been impossible to study its evolutionary relationships with the ''Epischoenus'' group of ''Schoenus''. Further material is needed to be able to reassess the taxonomy of this species.

Distribution and habitat

Collections of ''Schoenus adnatus'' have been made from the Cape Peninsula in the Western Cape Province to the

Steytlerville Steytlerville is a settlement on the R329 route in Sarah Baartman District Municipality in the Eastern Cape province of South Africa. The town is situated on the right bank of the Groot River, where the river emerges from a valley in the Grootr ...

region in the Eastern Cape Province of South Africa. ''Schoenus adnatus'' has primarily been collected from both moist and dry mountainous sites, ranging between 450 and 1375 m in elevation.

References

{{Taxonbar, from=Q42561866, from2=Q15591665 adnatus Southern African Schoenus Endemic flora of the Cape Provinces