Schoenus prophyllus

Sprophyllus-inflorescence-two.jpg

Schoenus prophyllus is a species of sedge endemic to the Agulhas Plain region of South Africa.[1]

Description

The key diagnostic character of S. prophyllus is its well-developed, firm, shiny spikelet prophylls with relatively long mucros compared to other species in the Schoenus cuspidatus group.[1]

Other species in the S. cuspidatus group that are similar to S. prophyllus are Schoenus bolusii, Schoenus calceolus, Schoenus purpurascens, and Schoenus submarginalis, which are all species with relatively short spikelets less than 4.0 mm.[1] However, the spikelets of S. prophyllus are ovate in shape, compared to the lancolate spikelets of S. bolusii and S. submarginalis.[1] Furthermore, the spikelets of S. prophyllus do not have the conspicuous reddish-purple streaking patterns adjacent to the glume margins that are found in S. bolusii and S. submarginalis.[1]

Schoenus calceolus often grows in close proximity, but its flattened culm base and straight leaves differ from those of S. prophyllus, whose leaves curl with age.[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] It is not clear whether Schoenus prophyllus forms hybrids with other southern African Schoenus species.[1]

Taxonomy

Schoenus prophyllus is a species in family Cyperaceae, tribe Schoeneae.[1] Other genera in tribe Schoeneae include Lepidosperma, Oreobolus, Costularia, Tetraria and Gahnia.[1][3][4] The most closely-related species to S. prophyllus are other southern African Schoenus species, specifically, species in the S. cuspidatus and allies group growing in close geographic proximity.[1]

Southern African Schoenus were once classified as Tetraria; however, based on molecular and morphological differences, the two groups are evolutionary distinct.[5] To ensure that this group of sedges is monophyletic (i.e. the genus only has closely-related species), the southern African Tetraria were transferred into Schoenus.[5] 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.[5]

Distribution and habitat

Growth form

Schoenus prophyllus is found in the southern Agulhas Plain region of South Africa.[1] The preferred growing substrate of this species is limestone. It grows at elevations less than 200 m.[1]

References

  1. ^ a b c d e f g h i j k l Elliott, T.L.; Barrett, R.L.; Muasya, A.M. (2019). "A taxonomic revision of Schoenus cuspidatus and allies (Cyperaceae, tribe Schoeneae)—Part 1". South African Journal of Botany. 121: 519–535. doi:10.1016/j.sajb.2018.11.021.
  2. ^ Levyns, M. (1947). "Tetraria and related genera, with special reference to the flora of the Cape Peninsula". Journal of South African Botany. 13: 73–93.
  3. ^ Viljoen, J.-A.; Muasya, A.M.; Barrett, R.L.; Bruhl, J.J.; Gibbs, A.K.; Slingsby, J.A.; Wilson, K. L.; Verboom, G.A. (2013). "Radiation and repeated transoceanic dispersal of Schoeneae (Cyperaceae) through the southern hemisphere". American Journal of Botany. 100 (12): 2494–2508. doi:10.3732/ajb.1300105.
  4. ^ Larridon, I.; Bauters, K.; Semmouri, I.; Viljoen, J.-A.; Prychid, C.J.; Muasya, A.M.; Bruhl, J.J.; Wilson, K.L.; Senterre, B.; Goetghebeur, P. (2018). "Molecular phylogenetics of the genus Costularia (Schoeneae, Cyperaceae) reveals multiple distinct evolutionary lineages". Molecular Phylogenetics and Evolution. 126: 196–209. doi:10.1016/j.ympev.2018.04.016.
  5. ^ a b c Elliott, T.L.; Muasya, A.M. (2017). "Taxonomic realignment in the southern African Tetraria (Cyperaceae, tribe Schoeneae; Schoenus clade)". South African Journal of Botany. 112: 354–360. doi:10.1016/j.sajb.2017.06.011.

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