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Juncus leiospermus

(Red Bluff Dwarf Rush)

Overview

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Threatened
Threat status

Common Names

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Common Names in English:

Red Bluff Dwarf Rush, Red Bluff Rush, Smooth-Seeded Rush

Description

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Family Juncaceae

Herbs, very rarely shrublike, perennial or annual , tufted or with erect or creeping rhizome. Stems erect, terete or laterally flattened. Leaves occasionally reduced to a bladeless or nearly bladeless sheath at base of stem (cataphyll) ; leaf sheath often shortly prolonged on both sides into a pair of auricles at leaf blade juncture; leaf blade of basal and cauline leaves usually linear or filiform , grasslike and flat, or terete, glabrous except for pilose margin on some grasslike blades. Inflorescence a panicle, corymb, or 1-flowered. Flowers bisexual or unisexual and plants dioecious, mostly wind pollinated, regular, usually small, usually 1- or 2-bracteolate at base. Perianth segments (3 or) 6, in (1 or) 2 whorls, free , usually greenish to brownish or blackish, rarely white or yellowish, glumelike. Stamens 3 or 6, if 6 then 3 opposite outer perianth segments; filaments thin; anthers basifixed , 2-loculed, dehiscing by longitudinal slits; pollen grains in tetrads . Ovary superior, 1-loculed, or divided by 3 septa and 3-loculed, or incompletely septate ; ovules 3 and inserted at base of ovary, or numerous and biseriate on 3 parietal placentas. Stigmas 3, papillose . Fruit a capsule, 1--3-valved, loculicidal. Seeds globose , ovoid , or fusiform , small, sometimes appendaged; appendage caudate ; embryo straight, minute, enclosed by fleshy endosperm.

About eight genera and ca. 400 species: widely distributed in temperate and cold regions of both hemispheres, in tropical regions restricted to high elevations ; two genera and 92 species (33 endemic) in China.[1]

Genus Juncus

Herbs, perennial or rarely annual , rhizomatous or cespitose. Culms round or flattened in cross section . Cataphylls often present at culm base. Leaves: sheaths open; blade flat, channeled , ensiform or terete , sometimes septate , margins involute . Inflorescences terminal or pseudoaxillary, monochasia or dichasia, usually with monochasial branches, cymes or 1--many heads in racemes or panicles; bracteoles 2 or absent. Flowers: tepals (4--) 6 in 2 whorls; stamens (2--) 3--6. Capsules 1-locular or 3-locular, septicidal . Seeds many, ellipsoid to ovoid , sometimes tailed .

Species ca. 300: worldwide except Antarctica.[2]

Physical Description

Species Juncus leiospermus

Herbs, annual , cespitose, 0.2--1.2 dm. Culms to 100, (0.2--) 0.4--0.8 mm diam.. Leaves 1/3--3/4 height of plant. Inflorescences terminal clusters , each with 1--7 flowers; bracts subtending inflorescence 2--8, round to acutely ovate , inconspicuous, 0.7--2.4 mm, membranous. Flowers: tepals reddish to black, narrowly lanceolate to oblong , 2--4.6 x´ 0.5--1.4 mm; inner series usually slightly longer than outer, apex obtuse to acuminate; stamens 3, filaments 0.5--1.4 mm, anthers 1--3.2 mm; style persistent , 1.4--4 mm, stigma 1.3--4 mm. Capsules reddish, 3-locular, globose to ellipsoid or oblong, 2--4.5 x´ 1--3 mm, nearly equal to sepals. Seeds ovoid , 0.35--0.45 mm. n = 16. Flowering and fruiting in spring . [source]

Plants from Butte and Calaveras Ccounties, California, tend to be smaller and consistently develop only one flower per culm; they may be recognized as Juncus leiospermus var. ahartii Ertter. [source]

Habit: Graminoid

Flowers: Bloom Period: February, March, April.

Habitat

Margins of vernal pools ; of conservation concern; to 500 m (Ref. 101550).

Biology

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Reproduction

Duration: Annual

Taxonomy

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Unambiguous Synonyms

  1. Juncus leiospermus var. ahartii Ertter.

Notes

Name Status: Accepted Name .

Publishing author : F.J.Herm. Publication : Leafl. W. Bot. 5: 113 1948

Similar Species

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Members of the genus Juncus

ZipcodeZoo has pages for 1350 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

J. abjectus · J. abortivus · J. acicularis · J. acumiantus · J. acuminatus (Sharp-Fruit Rush) · J. acuminatus debilis · J. acuminatus f. sphaerocephalus · J. acuminatus legitimus · J. acuminatus robustus · J. acuminatus var. paradoxus · J. acuminatus var. sensu · J. acutangulus · J. acutiflorus (Sharp-Flower Rush) · J. acutiflorus acutiflorus (Sharpflower Rush) · J. acutiflorus rugosus · J. acutiflorus × articulatus · J. acuto-maritimus · J. acutus (Sharp Rush) · J. acutus acutus (Spiny Rush) · J. acutus f. xanthosus (Spiny-Rush) · J. acutus leopoldii (Spiny Rush) · J. acutus littoralis · J. acutus sphaerocarpus · J. acutus subsp. leopoldii · J. adscendens · J. aemulans (Common Rush) · J. affinis · J. agrostophyllus · J. alatus · J. albescens · J. albicans · J. albidus · J. albus · J. aletaiensis · J. alexandri · J. alexandri alexandri · J. alexandri melanobasis · J. alexandri subsp. melanobasis · J. allioides · J. alpestris · J. alpiarticulatus · J. alpigenus · J. alpiniformis (Alpine Rush) · J. alpino · J. alpino-articulatus · J. alpinoarticulatus (Northern Green Rush) · J. alpinoarticulatus alpestris · J. alpinoarticulatus alpinoarticulatus · J. alpinoarticulatus americanus · J. alpinoarticulatus fischeranus · J. alpinoarticulatus fischerianus · J. alpinoarticulatus fuscencens · J. alpinoarticulatus fuscescens · J. alpinoarticulatus nodulosus (Alpine Rush) · J. alpinoarticulatus rariflorus · J. alpinoarticulatus subsp. alpestris · J. alpinoarticulatus subsp. americanus · J. alpinoarticulatus subsp. fischeranus · J. alpinoarticulatus subsp. fuscencens · J. alpinoarticulatus subsp. fuscescens · J. alpinoarticulatus var. macrocephalus (Northern Green Rush) · J. alpinus · J. alpinus alpinus · J. alpinus and · J. alpinus australis · J. alpinus f. obtusatus · J. alpinus fuscescens · J. alpinus insignis · J. alpinus nodulosus · J. alpinus subsp. turczaninovii · J. alpinus turczaninovii · J. alpinus var. americana · J. altus · J. amabilis · J. ambiguus (Seasice Rush) · J. ambiguus turkestanicus · J. ambiguus var. ossoraicus (Rush) · J. amplifolius · J. amuricus · J. anatolicus · J. anceps · J. andersonii · J. andicola · J. andicolus · J. angustifolius · J. annuus · J. anonymus · J. antarcticus · J. anthelatus (Greater Poverty Rush) · J. aquarrosus · J. aquaticus · J. arabicus · J. arcticus (Arctic Rush) · J. arcticus alaskanus · J. arcticus arcticus (Arctic Rush) · J. arcticus balticus · J. arcticus grubovii · J. arcticus littoralis (Arctic Rush) · J. arcticus mexicanus · J. arcticus pyrenaeus

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal January 30, 2008:

Identifiers

Footnotes

  1. Guofang Wu & Steven E. Clemants "Juncaceae". in Flora of China Vol. 24 Page 44. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. Ralph E. Brooks, Steven E. Clemants "Juncus". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/1/2009