Ledum palustre subsp. decumbens (Aiton) Hultén
Labrador tea, Muskeg Tea.
Ericaceae, bilberry family.
Kungl. Sv. Vetensk.-Akad. Handl., ser. 3, 8, 2: 8. 1930.
Ledum palustre L. var. decumbens Aiton Hort. Kew. 2: 65. 1789.
Ledum decumbens (Ait.) Lodd. ex Steud. Nomencl. Bot., ed. 2, 2: 20.
1841.
Rhododendron tomentosum (Stokes) Harmaja subsp. subarcticum (Harmaja) G. Wallace, Madroño, 39(1): 77. 1992.
Vegetative morphology. Plants shrubs; low shrubs; 10–20(–30) cm high; much branched, decumbent or ascending, with dark green, linear, aromatic, leaves. Aerial stems erect, or ascending, or decumbent; glabrous (old stems), or sparsely hairy (new growth); stem hairs spreading. Leaves distributed along the stems; alternate; evergreen. Stipules absent (prominent leaf bud scales present). Petioles 1–2 mm long; hairy; woolly. Petioles hairs spreading; wavy (hairs in the apical growing region of each stem are rusty brown; hairs on previous season's petioles are colorless or white). Leaf blade bases truncate, or attenuate (slightly). Blades 6–15 mm long; 1–2 mm wide. Blades spreading, or divaricate, or reflexed; leathery; linear; revolute; veins pinnate. Blades adaxial surface without sessile glands; glabrous. Blades abaxial surface hairy (with dense brown hairs along the mid-vein). Blades abaxial surface hairs very dense. Blades abaxial surface tomentose. Blades abaxial surface hairs rust-colored hairs; curved, or wavy; spreading. Blade margins entire; glabrous. Leaf apices rounded.
Reproductive morphology. Flowering stems absent. Inflorescence an umbel; axillary. Pedicels present. Pedicels bract leaves (5–)10–20 mm long. Flowers per inflorescence 5–15(–20); small, less than 5 mm in diameter or length (individual flowers, the cluster of flowers 1–2.5 cm in diameter). Calyx sepals 5; fused. Calyx green, or brown; with sessile glands; hairy (sparsely). Calyx hairs non-glandular (hairs among the sessile glands); brown (rusty). Petals free; 5 (usually); white; obovate; 2–3 mm long; 2–3 mm wide. Stamens 10. Anthers yellow; 0.8–1 mm long (without the horns found in some other Ericaceae species). Nectaries present. Gynoecia superior. Carpels syncarpous; 5. Ovaries ovate; glabrous (and with sessile glands). Styles 1. Placentation axile. Ovules 15–20. Fruit stalked; stalk 10–15 mm long. Fruit with calyx persisting; dry; a capsule; spherical; not distinctly flattened; dehiscent; teeth 5 (splitting from the pedicel end and remaining together at the style). Fruit 2–3.5 mm long; 1–3.5 mm wide; brown; glabrous and covered with papillae; surface appearing veinless. Seeds numerous.
Chromosome information. 2n = 26 and 52. 26 (2x). - Zhukova
(1980 southern Chukotka).
52 (4x). - Hagerup (1941a
Greenland?); Löve (1954b); Jørgensen et al. (1958 Greenland);
Löve and Löve (1975, 1982a arctic Canada); Zhukova and Petrovsky (1976
western Chukotka, 1987a north eastern Asia). Ploidy levels recorded 2x&4x.
Distribution. Northern hemisphere distribution: circumpolar; Greenland, Canada, United States, Eurasia, Siberia. Alaska, Yukon, Northwest Territories Islands, Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. Low arctic. Range in the Canadian Arctic Archipelago limited. Uncommon (but common where it occurs). Arctic Islands: Baffin, Victoria, Southampton.
Ecology and habitat. Substrates: imperfectly drained moist areas, or on seepage slopes; acidic. Habitats: moss-lichen heath on sunny cliffs and ledges (Porsild 1957). Common in most parts of the south; local towards the northern limit of its range. It grows chiefly in dry, places that are covered by snow in winter but not drifted over so deeply that the last snow melting reduces the growing season. It is characteristic of the sides of mounds and the upper levels of the banks of streams. Sometimes it is dominant over considerable areas and often found adjacent to marshes.
Indigenous knowledge. Inuit names: qijuktaaqpait (Baffin) means
"a large amount of fuel for a fire". (Ootoova et al. 2001);
mamaittuqutiit (Nunavik).
Medicinal teas are made from the leaves to
help general stomach ache and to strengthen a person after much bleeding To ease
breathing for people with tuberculosis or less serious ailments .Labrador tea
leaves may be chewed, placed on the chest or mixed with seal fat in an ointment
and rubbed on the chest (Anon 1984).
Labrador tea is picked all year round,
though it is stronger in fall and winter. ‘It doesn’t die. Like an
animal, like a dog, it keeps its fur, but in the spring the fur is new’.
The older the plant the better. (Anon 1984).
They are used to treat
toothaches and eye disorders. Labrador tea can heal canker sores in the mouth if
you place the leaves on them. The stems and leaves could also be boiled for tea
and used to treat sore throats. They are also known to moisten very dry hands
(Ootoova et al. 2001).
Anderson (1939) noted that the plant occurred "all
over the tundra" in Alaska and at that time was generally used for tea.
Andre and Fehr (2000) reported that Gwich'in people picked the leaves and
stems all year round for tea and also used the white flowers for tea in the
spring. Some people include the root of the plant to make a more concentrated
medicinal drink. This muskeg tea is considered good for children and is known to
be a relaxant and high in vitamin C. Inhaling the steam from this tea can help
clear congested nasal passages. The tea can be made, cooled and jarred for later
use, but elder advise against keeping muskeg tea for more than a few days.
BOiling or steeping the tea for more than 10 minutes is not recommended because
of some of the chemical compounds it contains (Walker 9184).
Economic uses. A.
Notes. Polunin (1940) stated that Labrador Tea varies little within
the Arctic Archipelago except in luxuriance, the plants generally being
prostrate and having small leaves, but sometimes ascending to 20 cm with stems
0.6 cm thick and much broader leaves. The plant seems always to flower and
generally to set fruit in abundance, even in its most northerly localities.
Whether or not the species regularly sets seed has not been established from
specimens in the herbarium at the eastern Canadian Museum of Nature.
Savile
(1969) considered the interrelationships of Ledum species and their rust
parasites and found that the rust, Chrysomyxa ledi var. ledi on
L. palustre subsp. decumbens is morphologically distinct from
C. ledi var. groenlandici, that occurs on L. groenlandicum
and suggested that this indicates the sharp distinctness of the two Ledum
taxa.
In a study of the germination ecology of Ledum
groenlandicum and L. palustre subsp. decumbens Karlin and
Bliss (1983) concluded that although the taxa are closely related they had
significantly different rates of germination, with 94.3% the total germination
occurring within 12 days for 1 month old seed of L. palustre subsp.
decumbens, while the corresponding value for L. groenlandica was
36.4%. Both species were found to require light in order for the seeds to
germinate, although the germination of L. groenlandicum was reduced in
far-red rich light regimes while that of L. palustre subsp.
decumbens was not.
Kudo (1995) studied the leaf traits and shoot
performance of L. palustre subsp. decumbens in accordance with
latitudinal change and found that at the at the Arctic sites L. palustre
produced leaves having longer life-span, higher nitrogen concentration, and
smaller size and specific leaf area in comparison with that at the temperate
mountain site. Although current leaf number and annual shoot growth were
smaller, leaf dry mass per stem was larger at the arctic site than at the
temperate one. At a taiga site those traits were within the range of the other
two sites, with the exception of leaf size and total leaf number per stem, which
was largest at the taiga site. Leaf life-span was negatively correlated to
specific leaf area and annual leaf number per stem and positively correlated to
leaf nitrogen concentration. Thus, with increasing latitude, L. palustre
produced fewer but more costly leaves and retained them for longer. Kudo (1995)
suggested that old leaves might have a resource storage function supporting new
leaf production.
There are good cladistic arguments for including
Ledum in Rhododendron (see Kron and Judd 1990, Syst. Bot. 15).
They are being kept apart in the Panarctic Flora checklist in accordance with a
still very prevalent practice. (Elven and Murray, personal communication 2001).
Illustrations. • Habitat. Dominant flowering plant with lichens. Plants are much branched, with ascending and prostrate stems, and linear leaves. Nunavut, Baffin Island, Iqaluit, growing beside stream near the end of the runway, 22 July 1982, J.M. Gillett 18995. CAN. • Close-up of plants. Plants with white umbel inflorescences. Nunavut, Baffin Island, Soper River Valley. July 2002. Aiken , s.n. • Close-up of growing tip. Growing tip with a dense cluster of leaves covered with brown deciduous hairs. Note adaxial surface of the leaves curled under leaving a stripe of brown hairs on the abaxial surface. Aiken, 2002. No voucher. • Close-up of growing tip. Growing tip with brown hairs. Aiken 2002. No voucher. • Plant habit. Flowering plants, with umbels of several small flowers with white petals. Nunavut, Baffin Island, Iqaluit. 22 July 1982, J.M. Gillett 18995. CAN. Large leaves and male flowers in picture belong to Rubus chamaemorus (Rosaceae). • Surface view of inflorescence. Cluster of flower buds in a developing umbel inflorescence. • Side-view of umbel. Flower buds developing in the axils of brown scale-like leaves that are shed as the buds expand. Aiken, 2002. No voucher. • Close-up of inflorescences. Plants with clusters of flower buds that are cream and tipped with red, as well as blooming flowers borne in umbels. Nunavut, Baffin Island, Iqaluit. 22 July 1982, J.M.Gillett.18995. CAN. • Close-up of flowers. Flowers with five free petals (free petals are unusual in the family) 10 anthers arranged in two whorls, one opposite and the alternate with the petals, and a single, long, slender style with a capitate stigma. Nunavut, Baffin Island, Iqaluit. 22 July 1982, J.M. Gillett. 18995. CAN. • Close-up of flowers. Free and fused petals in the same family. Note white flowers with free, overlapping petals. Compare with the bell-shaped fused petals of the lower flowers of cranberry . Photo by Lynn Gillespie. • Pinkish flowers. Surface view of inflorescence with pinkish tinged petals. Nunavut, Baffin Island, Apex. July, 2002. Aiken. No voucher. • Plants with pinkish flowers. • Pink flowers. Flowers with pink tips to the petals, anthers that have opened and a superior gynoecium at the base of a stout style that has a capitate stigma. Aiken, 2002. No voucher. • Habitat: plants in fruit. Brownish remains of faded petals are clinging to developing capsules. The bluish green leaves of the Ledum are 6–15 mm long, and contrast with the lime green, smaller leaves 2–6 mm long of crowberry (Empetrum nigrum). Nunavut, Baffin Island, Iqaluit. Aiken 97–060. CAN. Scale bar in cm. • Close-up of young fruit. Early fruit development. Remains of petals still cling at the base of the immature green or reddish fruit, and the red styles persist. and Baffin Island, Iqaluit. Aiken 97–060. CAN. • Umbel of capsules. Capsules that have opened from the base and are attached at the apex to the axis of the placentation. S. Aiken, 2001. No voucher. • Close-up of capsule. Dehisced capsules showing that that split from the bottom and remain attached to the axis of the ovary at the apex. Note the small lobes of the persisting calyx. • Arctic Island Distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
