Species: Juncus stygius var. americanus Buch.

comments | credits | copyright

Back to: Plants at Risk in Saskatchewan

Juncus stygius var. americanus Buch.

Species Image Gallery
(opens in a new window)

TAXONOMY

Family:

Juncaceae

Genus:

Juncus

Species Synonyms:

none

Common Names:

American bog rush
moor rush

DISTRIBUTION

Canada:

Yukon Territory – southwestern Mackenzie District – northern Saskatchewan – Ontario, Labrador – Newfoundland – Nova Scotia, southeastern British Columbia – southwestern Alberta

Saskatchewan:

northern – central Saskatchewan; Lake Athabasca – MacDowell

Ecoregion:

Mid-Boreal Upland, Churchill River Upland, Athabasca Plain, Tazin Lake Upland, Selwyn Lake Upland

HABITAT

Saskatchewan:

boggy lake shores and calcareous fens

Associated species:

Andromeda polifolia, Carex sp., Drosera anglica, Eriophorum viridicarinatum, Lysimachia sp., Rhynchospora alba, Rhynchospora fusca, Scheuchzeri palustris, Sphagnum sp., Trichophorum alpinum, Trichophorum caespitosum, Utricularia intermedia, Utricularia minor

RARITY STATUS

Provincial Status According
to Harms (2003):

Vulnerable

Nature Conservancy Status:

G5T5 S1S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Juncus stygius var. americanus is vulnerable in Saskatchewan because it is rare or uncommon and most local populations are small. No threats are known or anticipated for this species.

SPECIES DESCRIPTION

Height:

6 – 40 cm

Roots:

rhizome short, sparingly branched, slender

Stems:

perennial, loosely caespitose

Leaves:

basal leaves 1 – 3, cauline leaves 1 – 2, blade imperfectly septate, ascending, 8 – 18 cm long, much reduced distally, filiform; auricles rounded, scarious

Inflorescence:

heads 1 – 3, terminal, 1 – 4-flowered; peduncles 0.2 – 1 cm long; primary bracts nearly equal to or slightly surpassing heads

Flowers:

bracteoles absent; tepals nearly equal, lanceolate to ovate, apex acute, pale to reddish-brown; stamens 6, anthers much shorter than the filaments

Fruits:

capsules 6 – 8.5 mm long, exserted, mucronate, greenish; seeds about 1 mm long, fusiform, pale yellow to tan, broad-tailed

JUNCUS KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Inflorescence appearing lateral; leaves all basal	2
1 Inflorescence appearing terminal; may have at least one blade-bearing leaf on lower stem or leaves all basal	3

2 Bract stout, much shorter than stem; perianth parts usually darker brown; anthers commonly much longer than their filaments	J. balticus
2 Bract slender, as long as or longer than stem; perianth parts greenish to light brown; anthers commonly shorter than or equal to their filaments	J. filiformis

3 Leaves nodulose-septate (divided by cross-partitions), terete, or if flattened, strongly equitant	4
3 Leaves not nodulose-septate, terete or if flattened, not equitant	12

4 Leaves strongly flattened and equitant	5
4 Leaves terete or slightly compressed	7

5 Styles surpassing petals; seeds with a distinct tail-like appendage	J. tracyi
5 Styles equal to petals; seeds without a tail	6

6 Stamens 3; auricles lacking	J. ensifolius
6 Stamens 6; auricles present	J. saximontanus

7 Flowers in dense spherical heads	8
7 Flowers few to many in narrower heads	10

8 Heads solitary; rhizomes densely matted	J. mertensianus
8 Heads solitary; rhizomes elongate and creeping, often bearing tubers	9

9 Tepals reddish-brown, inner tepals longer than or equal to outer tepals; leaves 1 – 2 mm thick; sheaths with yellowish auricles	J. nodosus var. nodosus
9 Tepals greenish to dull brown, inner tepals shorter than outer tepals; leaves to 5 mm thick; sheaths with hyaline auricles	J. torreyi

10 Seeds about 1 mm long, with definite white tail-like appendages	J. brevicaudatus
10 Seeds less than 0.5 mm long, apiculate but without white tails	11

11 Anthers shorter than or equalling their filaments; perianth segments obtuse; capsule exceeding the perianth	J. alpinoarticulatus ssp. nodulosus
11 Anthers distinctly longer than their filaments; perianth segments acute; capsule shorter than or equal to the perianth	J. nevadensis

12 Each flower inserted singly on the branches of the inflorescences and subtended by a pair of small bractlets in addition to the bractlet at the base of the pedicel	13
12 Each flower subtended only by the single bractlet at the base of the very short pedicel	19


13 Roots fibrous; dwarf species, branched near base; annuals; leaf sheaths not auricled	J. bufonius
13 Rhizomes elongate or short if culms densely tufted; plants not dwarfed or branched near the base; perennials; leaf sheaths auricled or prolonged	14

14 Leaf sheaths extending to about halfway up the culm	J. compressus
14 Leaf sheaths confined to base or only extending to about one third of the way up the stem	15

15 Sepals erect, closely appressed to the capsule	J. vaseyi
15 Sepals spreading to ascending, not closely appressed to the capsule	16

16 Auricles short and round; leaf blades less than half the length of the culm	J. dudleyi
16 Auricles delicate and scarious; leaf blades usually greater than half the length of the culm	17

17 Capsule 3-loculed, nearly equalling the perianth; inflorescence compact	J. confusus
17 Capsule 1-loculed, distinctly shorter than the perianth; inflorescence a loose panicle	18

18 Auricles prolonged into a membranous projection 3 – 5 mm long	J. tenuis
18 Auricles shorter, up to 2 mm long, submembranous	J. interior

19 Seeds apiculate; leaves flattened and grass-like	J. longistylus
19 Seeds with distinct white tail-like appendages; leaves terete to somewhat compressed or deeply channelled	20

20 Culms arising from elongate rhizomes; perianth and capsules dark brown to black	J. castaneus ssp. castaneus
20 Culms not rhizomatous, may form tussocks; perianth and capsules pale	21

21 Capsules to 9 mm long; heads 1 – 2; lower cauline leaves 1 – 3	J. stygius ssp. americanus
21 Capsules to 4 mm long; heads solitary; leaves all basal	J. albescens