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Cyperus difformis

Higher Taxonomy
Family: CyperaceaeView DescriptionDichotomous Key

Common Name: SEDGE FAMILY
Habit: Annual, perennial herb, often rhizomed or stoloned, often of wet open places; roots fibrous; monoecious, dioecious, or flowers bisexual. Stem: generally 3-sided, generally solid. Leaf: generally 3-ranked; base sheathing, sheath generally closed, ligule generally 0; blade (0 or) linear, parallel-veined. Inflorescence: spikelets generally arranged in head-, spike-, raceme-, or panicle-like inflorescences; flower generally sessile in axil of flower bract, enclosed in a sac-like structure (perigynium) or generally not. Flower: unisexual or bisexual, small, generally wind-pollinated; perianth 0 or generally bristle like; stamens generally 3, anthers attached at base, 4 chambered; ovary superior, chamber 1, ovule 1, style 2--3-branched. Fruit: achene, 2--3 sided.
Genera In Family: +- 100 genera, 5000 species: especially temperate. Note: Difficult; taxa differ in technical characters of inflorescence, fruit. In Carex and Kobresia, what appear to be individual pistillate flowers in fact are highly reduced inflorescences (whether or not the same applies to staminate flowers is still under debate). In some other works (e.g., FNANM) these are called spikelets, and they are treated as being arranged in spikes. Here and in TJM (1993), what appear to be individual pistillate flowers are called pistillate flowers in Carex (and they are treated as being arranged in spikelets), but spikelets in Kobresia (and they are treated as being arranged into spikes). Though internally inconsistent, the approach here is consistent with traditional usage, and reflects a preference for character states that may be determined in the field. Molecular, morphological, and embryological evidence indicates that Eriophorum crinigerum is to be segregated to a new genus, as Calliscirpus criniger (A. Gray) C.N. Gilmour et al., along with a second, newly described species, Calliscirpus brachythrix C.N. Gilmour et al. (Gilmour et al. 2013); key to genera modified by Peter W. Ball to include Calliscirpus.
eFlora Treatment Author: S. Galen Smith, except as noted
Scientific Editor: S. Galen Smith, Thomas J. Rosatti, Bruce G. Baldwin.
Genus: CyperusView DescriptionDichotomous Key

Common Name: FLATSEDGE, NUTSEDGE, GALINGALE
Habit: Annual, perennial herb, glabrous. Stem: generally > 1, erect, 2--100 cm, 3-sided or cylindric. Leaf: basal; blade 0 or linear. Inflorescence: terminal, generally +- umbel-like, with spikes on rays; inflorescence bracts 1--9, leaf-like, spreading or erect; rays <= 20 cm; spikelets flat to not flat; flower bracts 2-ranked, 2--36, each with 1 flower in axil. Flower: bisexual; perianth 0; stamens (1--2) 3; stigmas 2--3. Fruit: (ob)ovoid, generally 3-angled, brown, generally not beaked.
Species In Genus: +- 600 species: temps, tropics worldwide. Etymology: (Greek: name for European Cyperus longus) Note: Mature fruit generally needed for identification. Cyperus gracilis R. Br., Cyperus owanii Boeck. [Cyperus ligularis L., misappl.], Cyperus regiomontanus Britton, Cyperus retrorsus Chapm., Cyperus virens Michx., urban weeds in California. Cyperus prolifer Lam. not in California.
eFlora Treatment Author: Gordon C. Tucker

Cyperus difformis L.
NATURALIZED
Habit: Annual 3--40 cm. Inflorescence: inflorescence bracts 2--3; rays 0--4, 6--30 mm; heads dense, +- spheric, +- yellow or +- purple; spikelets 50--100+, flat; flower bracts 6--30, 0.6--0.8 mm, obovate, yellow to yellow-brown. Flower: stigmas 3. Fruit: 0.6--0.8 mm, obovoid-ellipsoid, glossy.
Ecology: Ditches, pond shores, rice fields; Elevation: 100--500 m. Bioregional Distribution: GV, SW; Distribution Outside California: to Oregon, Utah, eastern North America; native to Old World. Flowering Time: Jul--Nov
eFlora Treatment Author: Gordon C. Tucker
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Citation for this treatment: Gordon C. Tucker 2016. Cyperus difformis, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=21811, accessed on July 26, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on July 26, 2016.


Cyperus difformis
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© 2003 Steve Matson
Cyperus difformis
click for enlargement
© 2003 Steve Matson
Cyperus difformis
click for enlargement
© 2003 Steve Matson
Cyperus difformis
click for enlargement
© 2003 Steve Matson
Cyperus difformis
click for enlargement
© 2003 Steve Matson
Cyperus difformis
click for enlargement
© 2003 Steve Matson

More photos of Cyperus difformis in CalPhotos


Geographic subdivisions for Cyperus difformis:
GV, SW;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.