Juncus tweedyi Rydb.:
United States (North America)

Juncus brevicaudatus (Engelm.) Fernald:
Canada (North America)
United States (North America)

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Northwestern Wyoming (Yellowstone National Park and Teton County), northeastern Utah (near Corinne in Box Elder County), adjacent southcentral Montana and southeastern Idaho. Also known from Rocky Mountain National Park in Colorado (Weber, 1996).

Populations from about around hot springs in the west have been separated as Juncus tweedyi Rydberg, but no morphologic distinction appears to exist between J. tweedyi and J. brevicaudatus.

Herbs, perennial, cespitose, 1.4--5.5(--7) dm. Culms erect, terete, 1--3 mm diam., smooth. Cataphylls 0--1, straw-colored to pink, apex acute. Leaves: basal 1--3, cauline 1--2; auricles 0.5--3 mm, apex rounded to truncate, scarious; blade terete, 1.5--25 cm x 0.5--2.5 mm. Inflorescences terminal panicles or racemes of 2--35 heads, 1--12 cm, branches erect; primary bract erect; heads 2--8-flowered, ellipsoid to narrowly obconic, 2--9 mm diam. Flowers: tepals green to light brown, lanceolate; outer tepals 2.3--3.1 mm, apex acuminate to rarely obtuse; inner tepals 2.5--3.2 mm, apex acuminate; stamens 3 (or 6), anthers 1/4--1/2 filament length. Capsules exserted, chestnut brown, imperfectly 3-locular, narrowly ellipsoid to prismatic, 3.2--4.8 mm, apex acute proximal to beak, valves separating at dehiscence. Seeds fusiform, 0.7--1.2 mm, tailed; body covered with whitish translucent veil. 2n = 80.

Juncus canadensis J. Gay var. brevicaudatus Engelmann, Trans. Acad. Sci. St. Louis 2: 436. 1866; J. canadensis var. coarctatus Engelmann; J. canadensis var. kuntzei Buchenau; J. coarctatus (Engelmann) Buchenau; J. kuntzei (Buchenau) Vierhapper; J. tweedyi Rydberg

Isotype for Juncus tweedyi Rydb.
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Status verified from secondary sources
Preparation: Pressed specimen
Collector(s): F. Tweedy
Year Collected: 1884
Locality: Yellowstone Park., Wyoming, United States, North America

Comments: Wet places around hot springs, mountain bogs, and margins of rivers and lakes.

Fruiting mid summer--fall. Generally in acidic or peaty moist sites, including emergent shorelines and aroundg hot springs; 100--2500 m; Alta., B.C., Man., N.B., Nfld. and Labr., N.S., Ont., P.E.I., Que., Sask.; Ariz., Colo., Conn., Maine, Md., Mass., Mich., Minn., Mont., N.H., N.Y., N.C., Oreg., Pa., R.I., Tenn., Utah, Vt., Va., W.Va., Wis., Wyo.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 21 - 80

Comments: Ten occurrences in Wyoming and one in Utah, but this is only part of the known range. Known from one occurrence in Colorado (Weber, 1996).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 2
Species With Barcodes: 1

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: G5 - Secure

United States

Rounded National Status Rank: N3 - Vulnerable

Rounded Global Status Rank: G3 - Vulnerable

Reasons: Juncus tweedyi is known from approximately ten occurrences in Wyoming, one occurrence each in Utah and Colorado, is known from Idaho (abundance unknown), and is not rare in Montana.

Comments: Recognized as distinct by Kartesz (1994 and 1999), but included in the widespread Juncus brevicaudatus by FNA (2000).