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Juncus effusus subsp. pacificus

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.
Species In Genus: 315 species: worldwide, especially northern hemisphere. 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]
Species: Juncus effususView Description 

Common Name: SOFT or LAMP RUSH
Habit: Perennial herb, cespitose, 60--155 cm; rhizome stout. Stem: 2--5 mm wide at base, above sheath; when fresh, upper stem smooth, shiny. Leaf: basal; blades 0. Inflorescence: appearing lateral, open; lowest bract cylindric, resembling stem, >> inflorescence; flowers generally many, single; bractlets 2 per flower. Flower: perianth parts 1.8--4.2 mm, +- equal, generally pale brown; stamens 3, filaments <= to > anthers. Fruit: +- = perianth, obovoid, +- truncate. Seed: 0.5 mm; appendage 1, minute. Chromosomes: 2n=40.
Note: Native and naturalized.
Juncus effusus subsp. pacificus (Fernald & Wiegand) Piper & Beattie
Stem: to 112 cm, 2.2--3.3 mm wide above sheath, 14 fine or broad ridges per side, pith solid. Leaf: sheath 6--19 cm, generally dark brown or +- black, papillate, uniformly dark, veins strongly converging at broadly asymmetrical summit, margins thickened, darker, edges overlapping in distal 1--1.5 cm. Inflorescence: generally open, 3--5 cm, branches ascending; bracts 7--24 cm, > inflorescence. Flower: perianth 2.3--2.8 mm, acuminate, generally pale, pressed to fruit, +- >= fruit, margins scarious; filaments = anthers. Fruit: 2.1--2.4 mm, oblong, truncate, inner partitions straight, chambers 3. Seed: 0.35--0.6 mm, 0.2--0.25 mm wide, brown, netted, +- asymmetrical.
Ecology: Seeps, shores, marshes, generally damp sunny ground; Elevation: < 2500 m. Bioregional Distribution: CA-FP (exc SW); Distribution Outside California: to British Columbia. Fruiting Time: May--Oct
Synonyms: Juncus effusus var. pacificus Fernald & Wiegand
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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Botanical illustration including Juncus effusus subsp. pacificus

botanical illustration including Juncus effusus subsp. pacificus


Citation for this treatment: Peter F. Zika 2015, Juncus effusus subsp. pacificus, in Jepson Flora Project (eds.) Jepson eFlora, Revision 3, /eflora/eflora_display.php?tid=79529, accessed on March 30, 2020.

Citation for the whole project: Jepson Flora Project (eds.) 2020, Jepson eFlora,, accessed on March 30, 2020.

Juncus effusus subsp. pacificus
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© 2004 Steve Matson
Juncus effusus subsp. pacificus
click for enlargement
© 2004 Steve Matson
Juncus effusus subsp. pacificus
click for enlargement
© 2009 Keir Morse
Juncus effusus subsp. pacificus
click for enlargement
© 2004 Steve Matson
Juncus effusus subsp. pacificus
click for enlargement
© 2008 Neal Kramer
Juncus effusus subsp. pacificus
click for enlargement
© 2004 Steve Matson

More photos of Juncus effusus subsp. pacificus in CalPhotos

Geographic subdivisions for Juncus effusus subsp. pacificus:
CA-FP (exc SW)
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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.
View all CCH records
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.

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).