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Vascular Plants of California
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Juncus acuminatus
TAPERED RUSH


Higher Taxonomy
Family: JuncaceaeView DescriptionDichotomous Key
Common Name: RUSH FAMILY
Habit: Annual, perennial herb generally from rhizomes. Stem: round or flat. Leaf: generally basal; sheath margins fused, or overlapping and generally with 2 ear-like extensions at blade junction; blade round, flat, or vestigial, glabrous or margin hairy. Inflorescence: head-like clusters or flowers 1, variously arranged; bracts subtending inflorescence 2, generally leaf-like; bracts subtending inflorescence branches 1--2, reduced; bractlets subtending flowers generally 1--2, generally translucent. Flower: generally bisexual, radial; sepals and petals similar, persistent, scale-like, green to brown or +- purple-black; stamens generally 3 or 6, anthers linear, persistent; pistil 1, ovary superior, chambers generally 1 or 3, placentas 1 and basal or 3 and axile or parietal, stigmas generally > style. Fruit: capsule, loculicidal. Seed: 3--many, generally with white appendages on 1 or both ends.
Genera In Family: 7 genera, 440 species: temperate, arctic, and tropical mountains. Note: Flowers late spring to early fall.
eFlora Treatment Author: Peter F. Zika, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: JuncusView DescriptionDichotomous Key


Common Name: RUSH
Habit: Rhizome 0 or generally with scale-like leaves. Stem: generally cylindric or flat. Leaf: blade well developed and cylindric or flat, occasionally closely resembling stem, or reduced to small point; crosswalls generally present; appendages generally present at blade-sheath junction. Inflorescence: generally terminal, appearing lateral when pushed aside by inflorescence bract; bractlets 0--2. Flower: sepals, petals similar; stamens generally 3 or 6(2); pistil 1, ovary chambers 1--3, placentas axile or parietal, stigmas generally 3(2). Seed: many.
Etymology: (Latin: to join or bind, from use of stems) Note: All species with leaf crosswalls may have leaves, stems swollen, deformed by sucking insects. Fruiting time given instead of flowering time. Plants included in TJM2 as Juncus brachyphyllus now treated in California as a new species, Juncus trilocularis (Zika 2012 Rhodora 114:309--329); Juncus bulbosus, Juncus dichotomus, and Juncus elliottii, only noted as naturalized in TJM2, now fully treated.
eFlora Treatment Author: Peter F. Zika
Reference: [Ertter 1986 Mem New York Bot Gard 39:1--90]
Juncus acuminatus Michx.
NATIVE
Habit: Perennial herb, cespitose, 20--80 cm; rhizome short. Leaf: generally basal; sheath appendages 1.5--5 mm, rounded; blade cylindric, crosswalls complete, obvious. Inflorescence: lowest bract < inflorescence; branches spreading; clusters generally 6--50, 5--20-flowered. Flower: perianth parts 2.5--3.5 mm, +- equal, narrowly acuminate, light brown to +- green; stamens generally 3, filaments +- > anthers. Fruit: generally <= perianth, light brown to red; chamber 1. Seed: 0.3--0.5 mm; appendages minute. Chromosomes: 2n=40.
Ecology: Shores, swales; Elevation: generally < 1300 m. Bioregional Distribution: NCo, KR, NCoRI, CaRF, n SN, GV, SnFrB; Distribution Outside California: to British Columbia, eastern North America, Mexico. Fruiting Time: Jul--Aug
Jepson eFlora Author: Peter F. Zika
Reference: [Ertter 1986 Mem New York Bot Gard 39:1--90]
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Citation for this treatment: Peter F. Zika 2015, Juncus acuminatus, in Jepson Flora Project (eds.) Jepson eFlora, Revision 3, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=29592, accessed on April 19, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on April 19, 2024.

Juncus acuminatus
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©2004 Steve Matson
Juncus acuminatus
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©2003 Steve Matson
Juncus acuminatus
click for enlargement
©2003 Steve Matson
Juncus acuminatus
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©2004 Steve Matson
Juncus acuminatus
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©2022 Neal Kramer

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Geographic subdivisions for Juncus acuminatus:
NCo, KR, NCoRI, CaRF, n SN, GV, SnFrB
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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).





 

Data provided by the participants of the  Consortium of California Herbaria.
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All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).