Silene acaulis (L.) Jacq.
Moss Campion.
Enum. Stirp. Vindob. 242. 1762.
Cucubalus acaulis L., Sp. Pl. 415. 1753.
Type: Linnaean herbarium 583.61 (LINN) lectotype, selected by Talavera and Muños Garmendia, Anales Jard. Bot. Madrid 45: 445. 1989.
Silene acaulis (L.) Jacq. subsp. arctica Á. and D.
Löve
Silene acaulis (L.) Jacq. subsp. subacaulescens (F.N.
Williams) C. L. Hitchc. and Maquire
Silene acaulis subsp. arctica Á. and D. Löve
Vegetative morphology. Plants 2–5 cm high; caespitose; forming compact, hemispherical or flat cushions up to 50 cm in diameter. Taproot present. Caudex present. Ground-level or under-ground stems horizontal; rhizomatous, or stoloniferous; elongate, or compact; 0.8–2 mm wide. Aerial stems erect and prostrate (plants grow from a tap root that develops many prostrate stems from which arise many compact erect branches); glabrous. Leaves distributed along the stems. Leaf blade bases cuneate. Blades (3–)6–12 mm long; 1–1.3(–1.6) mm wide. Blades spreading; herbaceous; lanceolate; flat; appearing single-veined. Blades adaxial surface dull; glabrous. Blades abaxial surface glabrous. Blade margins with non-glandular hairs (especially near the base). Leaf apices acute.
Reproductive morphology. Flowering stems glabrous, or hairy (sparingly). Flowering stem hairs pubescent; white or translucent (if applicable). Flowers solitary; medium-sized, 5–15 mm in diameter or length. Calyx sepals 5; fused; 4–6(–7.5) mm long. Calyx purple, or green and purple; herbaceous; tubular; glabrous. Calyx teeth equal or nearly so; 1.2–2 mm. Petals longer than the calyx; 5; pink, or white (occasionally); obovate; shallowly lobed; 7–9 mm long. Flowers unisexual, or bisexual. Stamens 10. Anthers yellow; ellipsoid; 0.8–1 mm long. Carpels 3. Ovaries ovate. Styles 3; 2.5–3.5 mm long. Ovules 15–30. Fruit ovoid; teeth 6. Fruit 6–8(–11) mm long; 3–4 mm wide; yellowish, or black. Seeds 0.8–1 mm long; brown; with surfaces verrucose.
Chromosome information. 2n = 24. 24 (2x). - Flovik (1940 Svalbard); D. Löve (1942 northernorthern Europe); Löve and Löve (1944b Scandinavia, 1956 Iceland, 1966b north eastern USA, 1975b, 1982 Central Canada, as 'arctica'); Sørensen and Westergaard in Löve and Löve (1948 Greenland); Jørgensen et al. (1958 Greenland); Sokolovskaya and Strelkova (1960 northern Russia); Sorsa (1963 Finlandand); Packer (1964 western Canada); Laane (1965 arctic Norway); Zhukova (1965a eastern Chukotka); Mosquin and Hayley (1966 northern Canada); Hedberg (1967 northern Canada); Johnson and Packer (1968 northwestern Alaska); Engelskjøn and Schweitzer (1970 Bear Island); Engelskjøn and Knaben (1971 Norway); Kovanda (1978 USA, as 'acaulescens'); Dawe and Murray (1979 Alaska); Dalgaard (1988 western Greenland). Several more southern counts. Ploidy levels recorded 2x.
Distribution. Northern hemisphere distribution: circumpolar and circumboreal; Greenland, Canada, United States, Eurasia. Yukon, Northwest Territories Islands, Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. Arctic and alpine. Range in the Canadian Arctic Archipelago widespread. Common. Arctic Islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry Islands, Banks, Victoria, Somerset, King William, Southampton (Mill, Salisbury, Nottingham, and Prince Charles Islands).
Ecology and habitat. Substrates: along streams, river terraces, tundra, slopes, ridges, cliffs; on seepage slopes, or dry, or moderately well drained areas; calcareous; gravel, sand, silt, till; with low organic content.
Notes. The leaves and branches of S. acaulis form a compact
cushion which provides considerable protection from the drying winds of winter.
Air flows over the cushion like the stream of air over an airplane wing and snow
easily covers the entire plant. In summer there is maximum exposed leaf surface
for photosynthesis and minimum exposure to the elements (Burt 2000).
Flowers
that are produced in great numbers are slightly fragrant and insect-pollinated.
In addition to normal bisexual flowers and female flowers with rudimentary
stamens (gynodioecy), bisexual flowers with reduced female organs are found
(Jonsell 2001).
Abbott et al. (1995) contrasted the molecular
diversity and derivations of populations of S. acaulis and Saxifraga
oppositifolia from the high Arctic and more southerly latitudes based on a
survey of allozyme diversity. They used populations of Silene acaulis
from Spitsbergen, Norway, Iceland, and Scotland and found that populations from
the high Arctic (Spitsbergen above 76°N) contained high levels of diversity
and were genetically similar to populations from more southern locations. A
restriction site analysis of chloroplast DNA (cpDNA) in S. acaulis
revealed that all populations contained a single identical cpDNA haplotype,
except one population from Norway, which also contained a second haplotype.
Abbott et al. (1995) suggested that S. acaulis populations in the
high Arctic have most likely been derived from immigrants that arrived from the
south after the last glacial period, while the evidence suggested that
Saxifraga oppositifolia may have northern stocks that survived the last
glaciation in high Arctic refugia.
The 'exscapa' name has been used
for the plants in the Amphi-Beringian area, but refers to a European endemic
according to Flora Europaea and is probably inapplicable in the Arctic. The
correct name for the arctic-alpine Pacific plants might be subsp.
arctica, or subsp. subacaulescens for the pedunculate ones (Elven
et al. 2002). As genetic evidence at this time does not justify
recognition of several taxa, the proposed subspecies are not applied here.
Illustrations. • Plant in habitat. Plant growing in crevices at rocky coast. Nunavut, Coppermine, 5 July, 1958. Photographed by Raymond Wood. CMN Photolibrary 578–327. • Plant in habitat. Plants forming compact, hemispherical or flat cushions up to 50 cm in diameter. Iceland, Bolungarvík, Stigahliđ, alt. 400–590, 66°11'N, 23°22'W. Photo by A. Brysting, June 1995. • Close-up of plant. Plants forming compact, hemispherical or flat cushions up to 50 cm in diameter. Nunavut, Ellesmere Island, Lake Hazen. Photographed by James H. Soper, 1958. CMN Photolibrary 585–2364. • Underside of plant. Underside of plant with a major tap root and many tightly packed branches that make up the cushion. Nunavut, Baffin Island, Iqaluit. Aiken and Mallory. 2002. No voucher. • Close-up of plant. Compact cushion plant with developing fruits, growing on gravel. Nunavut, Baffin Island, Iqaluit, 22 July 1982. J.M. Gillett 18991. CAN. • Close-up of flowers. Flowers on the cushion; petals pink (or occasionally white) and shallowly notched. Nunavut, Iqaluit, Baffin Island, 22 July 1982. J.M. Gillett 18991. CAN. • Close-up of fruit. Unripe capsules, exceeding the fused calyx sepals. Norway, Espedal. Photo by R. Borge, June 1976. With permission of the Botanical Museum, University of Oslo, Norway. • Close-up of fruit. Cut through an unripe capsule; free central placentation. Norway, Espedal. Photo by R. Borge, June 1976. With permission of the Botanical Museum, University of Oslo, Norway. • Drawing of plant. Plant forming cushions or mats from a stout central taproot. Botany Division. 1974. CMN Photolibrary 574–827. • Distribution map.
Cite this publication as: ‘A.K. Brysting, P.J. Scott, and S.G. Aiken 2001 onwards. Caryophyllaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000) , and Aiken, Dallwitz et al. (1999) should also be cited (see References).
