Juncus acuminatus

Michx.

Sharp-fruit Rush

G5Secure Found in 1 roadless area NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
Identity
Unique IDELEMENT_GLOBAL.2.158814
Element CodePMJUN01030
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderJuncales
FamilyJuncaceae
GenusJuncus
Other Common Names
Jonc à tépales acuminés (FR) tapertip rush (EN) Tapertip Rush (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Taxonomic Comments
In order to best serve nomenclatural stability, Knapp et al. (2022) propose to conserve the name Juncus acuminatus Michx. for this species in spite of it being a later homonym of J. acuminatus Balb. (which is now regarded as a synonym of J. arcticus Willd.). The authors also identify the next oldest legitimate name as J. paradoxus E. Mey. which would be the new name for this species if the proposal is not accepted.
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-28
Change Date1984-06-06
Range Extent Comments
ME to B.C., south to GA, MO, AZ, and CA. Sparse.
Ecology & Habitat

Description

Tapered Rush is a tufted, grass-like perennial with erect stems that are 3-8 dm high and fibrous roots. Leaf blades septate: they are are tubular and divided internally into cross-sections. The leaf sheaths surround the stem and have a pair of membranous appendages, or auricles, on either side where the blade is attached. Flowers are borne in 5-20 hemispheric heads on the ends of spreading stalks in an open inflorescence subtended by a single leaf-like bract. Each flower is subtended by a single scale-like bract and has 6 undifferentiated, sharply pointed perianth segments that are 3-4 mm long and light brown or greenish in color. There are usually only 3 stamens. The light brown, 3-sided seed capsules are lance-shaped and 3-4 mm long with pointed tips. Each seed is ca. 0.5 mm long and has a net-like surface with a short tip at one end.

Diagnostic Characteristics

The septate leaves and flowers subtended by a single bract and having only 3 stamens separate J. ACUMINATUS from our other non-rhizomatous rushes. JUNCUS is a large and difficult genus to distinguish, so a technical key should be consulted. Mature fruit is necessary for positive determination.
Other Nations (2)
United StatesN5
ProvinceRankNative
KentuckyS5Yes
OregonSNRYes
New MexicoSNRYes
OklahomaSNRYes
MissouriSNRYes
West VirginiaS5Yes
IdahoSNRYes
GeorgiaSNRYes
HawaiiSNANo
WashingtonSNRYes
TennesseeSNRYes
VermontS1Yes
VirginiaS5Yes
ConnecticutSNRYes
FloridaSNRYes
District of ColumbiaSNRYes
ArizonaSNRYes
MichiganSNRYes
North CarolinaS5Yes
Rhode IslandSNRYes
LouisianaSNRYes
New YorkS5Yes
OhioSNRYes
NebraskaS1Yes
KansasS3Yes
New JerseyS5Yes
MontanaS1Yes
MaineSNRYes
CaliforniaSNRYes
South CarolinaS5Yes
IndianaSNRYes
TexasSNRYes
MississippiSNRYes
WisconsinSNRYes
ArkansasSNRYes
AlabamaSNRYes
IowaS4Yes
New HampshireSNRYes
ColoradoS1Yes
IllinoisS4Yes
DelawareS4Yes
PennsylvaniaS5Yes
MarylandSNRYes
MassachusettsSNRYes
CanadaN5
ProvinceRankNative
British ColumbiaS5Yes
QuebecS1Yes
OntarioS3Yes
Nova ScotiaS3Yes
Plant Characteristics
Economic Value (Genus)No
Roadless Areas (1)
Arizona (1)
AreaForestAcres
Happy ValleyCoronado National Forest7,972
References (3)
  1. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  2. Knapp, W.M., G.A. Levin, and K. Gandhi. 2022. (2903) Proposal to conserve the name <i>Juncus acuminatus</i> Michx. against <i>J. acuminatus</i> Balb. (Juncaceae) and including the lectotypification of <i>J. paradoxus</i>. Taxon 71(4):905-906.
  3. Lesica, P. 1991d. The rare vascular plants of Pine Butte Preserve. Unpublished report to The Nature Conservancy, Montana Field Office, Helena. 15 pp.