Rhynchospora
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Rhynchospora
| Rhynchospora | |
|---|---|
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| Rhynchospora fascicularis | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| (unranked): | Commelinids |
| Order: | Poales |
| Family: | Cyperaceae |
| Genus: | Rhynchospora Vahl |
| Species | |
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About 400; see text |
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Rhynchospora (Beak-rush or Beak-sedge) is a genus of about 250-300 species of sedges with a cosmopolitan distribution. The genus includes both annual and perennial species, mostly with erect 3-sided stems and 3-ranked leaves. The achenes bear a beak-like tubercule (hence the name “beak-rush”, although the plants are sedges, not rushes) and are sometimes subtended by bristles. Many of the species are similar in vegetative appearance, and mature fruits are needed to make a positive identification.
The infloresences (spikelets) are sometimes subtended by bracts which can be leaf-like or showy.
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Contents
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Ecology
Rhynchospora occurs on all continents except Antarctica, but is most diverse the neotropics [1]. It is most frequent in sunny habitats with wet, acidic soils [2]. In marshes and savannas, Rhynchospora may be the dominant form of vegetation.
Taxonomy
Contemporary taxonomic treatments include Rhynchospora and the related genus Pleurostachys in the tribe Rhynchosporae, a well-supported clade within Cyperaceae [3]. The most comprehensive monograph of the genus [4] divides Rhynchospora into two subgenera and 29 sections. A recent molecular analysis [5] identifies two primary clades within the genus, with well-supported subgroups that agree with several of the sections identified by Kükenthal. However, this molecular analysis also suggests that Pleurostachys is embedded within one of the primary clades of Rhynchospora and that several of the recognized sections are not monophyletic.
- Selected species
- Rhynchospora alba - White Beak-sedge. Europe.
- Rhynchospora californica - California beaked-rush, occurring in Marin and Sonoma County, California
- Rhynchospora capitellata - Brownish Beak-sedge
- Rhynchospora colorata - White Star Sedge. Southeast North America.
- Rhynchospora fusca - Brown Beak-sedge. Europe.
- Rhynchospora glomerata - Clustered Beak-sedge. North America.[6]
- Rhynchospora knieskernii - Knieskern's Beak-sedge.
- Rhynchospora nervosa - Tropical New World.
References
- ^ Thomas, W.W. 1992. A synopsis of Rhynchospora (Cyperaceae) in Mesoamerica. Brittonia 44:14–44.
- ^ Kral, R. 2002. Rhynchospora. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 15+ vols. New York and Oxford. Vol. 23 pp. 200-239.
- ^ Muasya, A. M., J. Bruhl, D. A. Simpson, A. Culham and M. W. Chase. 2000. Suprageneric phylogeny of Cyperaceae: A combined analysis. pp. 593–601. In: K. Wilson and D. Morrison (eds.) Monocots: Systematics and Evolution. CSIRO: Melbourne.
- ^ Kükenthal, G. 1949-1951. Vorarbeiten zu einer Monographie der Rhynchosporoideae. Rhynchospora. Bot. Jahrb. Syst. 74, 75
- ^ Thomas W.W., A.C. Araujo, and M.V. Alves. 2009. A Preliminary Molecular Phylogeny of the Rhynchosporae (Cyperaceae). Botanical Review 75:22-29.
- ^ Rhynchospora glomerata (L.) Vahl USDA Plants Profile. 23 Nov 2011
External links
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