Flora of the Canadian Arctic Archipelago

DELTA Home

S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Juncus arcticus Willd.

English: Arctic bog rush,

French: Jonc arctique,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Juncaceae, Rush family.

Published in Sp. Pl. ed. 4: 206. 1799.

Type: Described from northern Scandinavia ('Lapland').

Synonymy. Juncus arcticus subsp. alaskanus Hultén, Lunds Univ. Årsskr., n. f., avd. 2, 39, 1: 418. 1943.

Juncus balticus Willd. var. alaskanus (Hultén) A.E. Porsild, Bull. Natl. Mus. Canada 146: 60. 1957.

Vegetative morphology. Plants (10–)15–40(–50) cm high (or 100 cm high on continental North America); perennial herbs; not caespitose; sometimes vegetatively proliferating by fragmentation (ice rafting of rhizomes occasionally). Only fibrous roots present. Ground level or underground stems horizontal (robust); rhizomatous, or stoloniferous; elongate, or compact. Ground level or underground stems scales present (these usually interpreted as sheaths), or absent. Aerial stems erect (irregularly striate, non-flowering stems few or absent). Leaves absent or leaf teeth; merely cataphylls (in contrast to other Juncus taxa, prominent and reddish brown).

Reproductive morphology. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems without leaves. Leaf or reduced bract subtending the base of the inflorescence present; conspicuous and leaf-like (1.5–5 cm long, erect and stiff); similar in length to the inflorescence. Flower orientation flowers side by side in a horizontal plane. Inflorescences head-like; lateral (appearing axillary at the base of the bract); dense; 0.6–1 cm long. Pedicels absent (or various lengths). Bisexual spike(s) with empty bracts at the base. Floral bracts apices entire. Flowers per inflorescence 2–5(–8) (or more)); small (or just over 5 mm; more or less sessile). Sepals conventional (brown tepals); 3; free; brown (margins hyaline); scarious. Calyx glabrous. Petals conventional (brown tepals); free; shorter than the calyx, or same length as the calyx; 3; brown (scarious, loosely subtending the capsule at maturity; usually slightly shorter, margins scarious to clear); lanceolate; unlobed; 3–5 mm long; 1.3–1.7 mm wide. Stamens 6. Anthers 0.7–1(–2.2) mm long (shorter or as long as their slender filaments). Ovary superior; carpels 3; syncarpous. Styles 3; free; 0.9–1.5 mm long. Stigmas per ovary 3. Ovules per ovary 20–100. Fruit sessile; with calyx persisting; dry; a capsule; ovoid, or elongate-cylindrical, or obovate; black, or brown (3-locular or infrequently pseudo-3-locular; oblate to narrowly ovoid); 3.5–4.5 mm long; 1.8–2.2 mm wide (equal to or exceeding the perianth); not distinctly flattened (but concave and slightly notched at the apex); dehiscent. Seeds 30–100; 0.4–1 mm long; brown (dark amber; oblate to ellipsoid); surfaces smooth.

Chromosome information. 2n = 80, 84. Juncus arcticus Willd. subsp. arcticus

2n = 80. Löve and Löve (1956, Iceland); Jørgensen et al. (1958, Greenland, including separate counts by Holmen and by Christiansen); Löve and Ritchie (1966, northern Canada); Engelskjøn and Knaben (1971, southern and northern Norway); Zhukova and Petrovsky (1980, western Chukotka);

Yurtsev and Zhukova (1982, northern Siberia); Zhukova (1982, northeastern Asia); Kovtonjuk (1989, Siberia);

2n = 84. Snogerup (1971, Scandanavia); Löve (1981d, northern Canada).

2n = about 100. Löve and Löve (1944a, northern Europe), omitted by Löve and Löve (1975);

Juncus arcticus Willd. subsp. alaskanus Hultén;

2n = 80. Knaben (1968, Alaska); Zhukova and Petrovsky (1976, eastern Chukotka).

Ecology and habitat. Substrates: around the margins of ponds, marshes, along streams (on sand bars), seashores (in deltas, or in marshes just above the high tide line, frequently associating with obligate halophytes); imperfectly drained moist areas; sand, clay (alluvial); with low organic content, with high organic content; acidic, or calcareous, or non-calcareous (indifferent). A pioneer species.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador (?). Range in the Canadian Arctic Archipelago limited. Common (where it occurs). Arctic. Arctic islands: Baffin, Ellesmere (records from Ellesmere Island were not known to Porsild 1957), Banks, Victoria, Southampton.

Northern hemisphere distribution. Circumpolar, or circumboreal (in the collective meaning). Northern Iceland, Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, West Greenland, East Greenland.

General notes. Elven et al. (2003) noted that the most recent North American treatment (Brooks and Clemants 2000) of J. arcticus recognised three varieties, two as arctic (var. alaskanus and var. balticus). Brooks and Clemants (2000) stated that J. arcticus is "a wide-ranging and obviously polymorphic complex that has not read the literature."

Juncus arcticus and J. balticus were both originally described from northern Europe. In most of this area they are very different in general morphology and in many detailed features. When comparing a series of 'typical' plants, no one would be in doubt about them being two different species. But even in Europe the separation of them as species is now disputed.

Another problem to be resolved was whether the 'alaskanus' entity belonged as a race of J. arcticus or of J. balticus. Brooks and Clemants (2000) included most northern North American (including Greenland) material in their concept of var. alaskanus, but they allowed that "perhaps J. arcticus var. alaskanus is not distinct from the Eurasian J. arcticus var. arcticus". That is certainly the case with much of the Greenland material, which is indistinguishable from the northern European (type area) and Svalbard material. The Alaskan material is more different, but not very much so. The 'alaskanus' entity is obviously much closer to the Northern European 'arcticus' entity than it is to the northern European 'balticus'.

Elven et al. (2003) considered the options were either to "regard the entire complex as one large, polymorphic species with 4–5 subspecies, as two species (J. arcticus with the 'arcticus', 'alaskanus', and 'sitchensis' entities; J. balticus with the 'balticus' and 'littoralis' entities), or as numerous ill-defined, morphologically overlapping, and probably fully interfertile species." The 'littoralis' race is more southern, ranging from Alaska to Newfoundland, often inland (Porsild and Cody 1980).

In May, 2005, Elven and Aiken examined CAN specimens from Banks and Victoria Islands and concluded that they belong to subsp. arcticus. This was not expected, as subsp. arcticus is typified from Scandinavia. Subspecies arcticus has relatively delicate plants with small flowers in compact inflorescences; plants of subsp. alaskanus are coarse, with diffuse inflorescences (Elven, personal communication, May 2005). Also, Porsild and Cody (1980) had reported J. balticus subsp. alaskanus Hultén (synonymous with J. arcticus subsp. alaskanus Hultén) on adjacent continental North America, and also on Victoria and Banks Islands. Elven and Aiken could not separate the specimens collected in the eastern Canadian Arctic Islands on the anther, inflorescence, or capsule characters usually used to recognise separate subspecies. Therefore, currently, subsp. arcticus is recognised on the Canadian Arctic Islands.

Fontenla et al. (2001) studied the mycorrhizal status of plant species in northwestern Patagonia communities representative of Patagonian steppe and marshes including Juncus arcticus.

Cooper and MacDonald (2000) used J. arcticus in a revegetation experiment to restore rich fens that had been mined in Colorado. They found that Juncus arcticus and willow cuttings had differing patterns of survival with respect to the annual maximum height of the water table and that dominant species can be successfully reintroduced to mined surfaces with the appropriate hydrologic conditions. Cooper and MacDonald (2000) stated that human intervention would be necessary to rapidly re-establish plant cover and that the slow rate of peat accumulation means that restoration of the mined fens will require hundreds, if not thousands, of years.

Illustrations. • Habitat. Plants growing with Salix in the shelter of a rock at high tide level. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–071. CAN. Scale bar in cm. • Base of plant. Close-up of base of plant showing straight horizontal rhizome, stems arising from the rhizome with cataphylls replacing leaves. Nunavut, Baffin Island, Iqaluit. July, 2004. Photographed by M. LeBlanc. • Habitat. Meadow of Juncus arcticus with plants in rows from the underground rhizomes. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–085. CAN. • Close-up of plants. Stems arising in rows from underground rhizomes. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–085. CAN. Scale bar in cm. • Bract subtending inflorescence. Inflorescence borne laterally at the top of a green stem and subtended by a long bract. Flowers have brown tepals, yellow anthers and curly pink stigmas. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–085. CAN. • Close-up of inflorescence. Long bract subtending inflorescence with two open flowers and one or two buds. Open flowers have brown tepals, yellow anthers, and three curly pink stigmas. Aiken and Brysting 01–085. CAN. • Close-up of inflorescence in fruit. Plants with capsules blunt or slightly concave at apex. The inflorescence appears lateral owing to a terete bract that looks like a continuation of the stem. CAN 507382. • Arctic Island Distribution.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

.

Contents