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Juncus tenuis

POVERTY or SLENDER 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 tenuis Willd.
NATIVE
Habit: Perennial herb, cespitose, stem 20--60 cm, generally 0--1 strong ridges per side. Leaf: sheath margins membranous, sheath appendages generally acute to acuminate, thin, +- translucent, generally 1--8 mm until late in season when generally smaller or 0; blade with flat side toward stem, 1/2 to = stem, 1--1.3 mm wide, not stiff, crosswalls 0. Inflorescence: +- open; lower bracts leaf-like, generally > inflorescence; branches unequal; flowers 1, generally > internodes, +- denser near branch tips; bractlets 2 per flower, acute to blunt. Flower: perianth parts 3--4.5 mm, +- equal, lanceolate, acuminate, spreading in fruit, green to +- red or pale brown; stamens 6, filaments >> anthers. Fruit: < perianth, widely ovoid, blunt to acute; chamber 1, partitions incomplete. Seed: 0.4--0.5 mm, oblong; appendages minute, blunt. Chromosomes: 2n=80.
Ecology: Uncommon. Damp places; Elevation: generally < 1500 m. Bioregional Distribution: NW, CaR, SN (exc Teh), GV, CCo, SnGb, MP; Distribution Outside California: North America, introduced worldwide except Antarctica. Fruiting Time: Jun--Sep Note: Hybridizes with Juncus occidentalis.
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 tenuisbotanical illustration including Juncus tenuis


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Citation for this treatment: Peter F. Zika 2015, Juncus tenuis, in Jepson Flora Project (eds.) Jepson eFlora, Revision 3, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=29725, accessed on December 02, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on December 02, 2024.

Juncus tenuis
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©2005 Steve Matson
Juncus tenuis
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©2003 Steve Matson
Juncus tenuis
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©2008 Keir Morse
Juncus tenuis
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©2005 Steve Matson
Juncus tenuis
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©2003 Steve Matson

More photos of Juncus tenuis
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Geographic subdivisions for Juncus tenuis:
NW, CaR, SN (exc Teh), GV, CCo, SnGb, MP
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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 occurrence).






 

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 Flowering-Fruiting Monthly Counts

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).