Flora of the Canadian Arctic Archipelago
English: Arctic saxifrage,
French: Saxifrage hyperboréale.
Saxifragaceae, Saxifrage family.
Published in Chloris Melvill. 16. 1823.
Type: Canada: Melville Island, James Ross 1819–20, selected by Webb and Gornall, Man. Saxifrag. 148. 1989. Lectotype: BM.
Synonymy. Saxifraga flexuosa Sternb., Revis. Saxifrag., Suppl. 2: 38. 1831.
Saxifraga rivularis L. var. (gamma) purpurascens Lange, Meddel. Grønland 3 (Consp. Fl. Groenl.): 62. 1880.
Saxifraga rivularis L. var. flexuosa (Sternb.) Irmsch. in Engl., Pflanzenreich IV-117, 67: 282. 1916.
Saxifraga rivularis L. subsp. flexuosa (Sternb.) Gjærev., Kongel. Norske Vidensk. Selsk. Skr. (Trondheim) 1963, 4: 61. 1964.
Saxifraga rivularis auct., non L., 1753.
Vegetative morphology. Plants (1.5–)6–10(–12) cm high; perennial herbs; caespitose. Ground level or underground stems vertical (short). Horizontal stems at ground level, branching extensively to shape plant habit as low plants may be cushion-like. Caudex present. Aerial stems erect. Leaves mainly basal; alternate; dying annually and non-persistent. Petioles (2–)10–20(–35) mm long; glabrous, or hairy; pilose (if applicable). Petiole hairs longer than the diameter of the petiole. Leaf blades simple. Leaf blade bases obtuse, or cuneate. Blades (2–)3–5(–6) mm long, (3–)5–8(–9) mm wide, triangular (or obtrangular), flat, veins palmate or with inconspicuous veins. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blades lobed (with 3, rarely 5 lobes). Blade margins entire, glabrous; degree of incision 50–70%. Hydathodes present and conspicuous, or present but inconspicuous. Blade apices acute.
Reproductive morphology. Flowering stems two or more per plant; conspicuously taller than the leaves; with leaves (not lobed and usually not close to the flowers). Flowering stems hairy. Flowering stems pilose. Flowering stem hairs longer than the diameter of the flowering stem; white or translucent, or transparent with deep purple cross-walls; glandular hairs present. Flowers solitary, or in inflorescences (occasionally with 2 flowers). Inflorescences paniculate (if applicable); 1–1.5 cm long. Pedicels present (when 2 flowers are present); with glandular hairs. Flowers per inflorescence 1–3; small, or medium-sized. Sepals conventional; 5; free; 1–2 mm long; 1.5–2.5 mm wide; green and purple. Calyx glabrous (hypanthium hairy). Petals conventional; free; longer than the calyx; 5; white (in albino form), or white and purple (as a tinge of colour at the base of each petal); obovate (widely or narrowly so); unlobed; 3.5–4.5 mm long; 0.8–1.5 mm wide. Stamens 10. Anthers 0.2–0.4 mm long. Nectaries present. Receptacle 3–4 mm high (a well-developed hypanthium). Ovary partly inferior; carpels 2; partly fused. Ovaries glabrous (where visible). Placentation axile. Ovules per ovary numerous. Fruit with calyx persisting; dry; a capsule; urceolate; golden brown; 7–9 mm long; 3.5–4 mm wide; glabrous; surface venation ribbed; dehiscent; splitting to the base into separate segments. Seeds numerous; 0.4–0.5 mm long; brown, or yellowish; surfaces smooth.
Chromosome information. 2n = 26.
(2n) = 26. Flovik (1940, Svalbard); Holmen (1952, Greenland); Jørgensen et al. (1958, Greenland); Packer, in Löve and Löve (1961a, northern Europe); Löve and Solbrig (1964b); Löve and Löve (1965, 1966b, northeastern USA); Johnson and Packer (1968, northwestern Alaska); Zhukova (1968, 1969, northeastern Asia; 1980, southern Chukotka); Engelskjøn and Schweitzer (1970, Bear Island); Löve (1970a, Iceland, otherwise not recognised for Iceland); Krogulevich (1971, Siberia, perhaps south of the accepted range of the species); Zhukova and Petrovsky (1971, Wrangel Island; 1980, western Chukotka; 1987a, northeastern Asia); Zhukova and Tikhonova (1971, Chukotka); Zhukova et al. (1973, north and northeastern Asia); Engelskjøn (1979, Svalbard); Yurtsev and Zhukova (1982, northern Siberia); Borgen and Elven (1983, Svalbard); Devyatov et al. (1997, northern Siberia); Brochmann (unpublished Svalbard).
Ploidy levels recorded 2x.
Ecology and habitat. Substrates: along streams, seashores; imperfectly drained moist areas, seepage slopes; gravel, sand, till, moss; with low organic content, with high organic content, peat; calcareous. Just above tide line (CAN 25877); gneiss, tertiary and coal deposit (CAN 65807); steep slope with carbonate cobbles and boulders, with a moderate amount of fines, on west side of gully (CAN 526885); in fine wet sand below high tide level on gently sloping flats; wet places among coarse boulder litter (CAN 453888); stony, silty diamicton, colluvial, fluvial deposit; growing in moist ground beside a river.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut (check Quebec), Labrador. Range in the Canadian Arctic Archipelago widespread. Common. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Ellef Ringnes, Parry islands (Bathurst, Cameron, Eglington, Helena, Mackenzie King, Melville), Cornwallis, Banks, Victoria, Southampton.
Northern hemisphere distribution. Circumpolar. KaninPechora, Svalbard Franz Joseph Land, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. This circumpolar arctic-alpine species differs from S. rivularis s.s. in its tiny size, absence of underground stolons and more developed hypanthium. These distinctions, however, are not always well expressed (Zhmylev, in Elven et al. 2003). Jørgensen & Elven (in Elven et al. 2005) said that "these distinctions (except for the stolons) are not always obvious, but Jørgensen (2004) and Jørgensen et al. (2006) summarised some additional differences."
Polunin (1940) noted that this plant may penetrate farther into very late-melting snow patches than any other angiosperm. It is frequent almost everywhere, and in places rather abundant, although so small as to be often overlooked.
Löve and Löve (1975) sorted the diploid counts into two subspecies of S. hyperborea: subsp. hyperborea in the northern Arctic; and subsp. debilis in the broadly Pacific area, including counts around the Bering Strait, in western North America, and also a southern Siberian count (Krogulevich 1971, see above).
There are two basic diploids (2n = 26) represented by the amphi-Pacific and amphi-Beringian S. bracteata D. Don and the circumpolar and arctic-alpine S. hyperborea R. Br. The Cordilleran S. flexuosa Sternb. is inseparable from S. hyperborea in molecular markers and also nearly inseparable in all studied morphological characters which overlap in every character considered. It probably represents some kind of segregate south of the Cordilleran glaciation but has either survived in or reinvaded the Beringian areas. Transitions between the 'flexuosa' and 'hyperborea' morphologies are very abundant in northern Alaska and Yukon. The amphi-Atlantic Saxifraga rivularis L. and the now amphi-Beringian S. arctolitoralis Jurtz. and V.V.Petrovsky are allotetraploids.
Illustrations. • Habitat: Cape Dorset. Bluish green clumps of Saxifraga rivularis with white flowers in foreground and left (Aiken 05–095) growing with reddish more erect plants of Saxifraga hyperborea, centre (Aiken 05–096). Nunavut, Baffin Island, Cape Dorset. 5 August, 2005. Aiken. CAN 586964. • Habitat. Plants growing between the markers beside a run-off stream. Nunavut, Baffin Island, Iqaluit. 6 July, 2004. Aiken and LeBlanc 04–009. CAN 586481. • Close-up of plants. Plants with most leaves close to the ground. Flowers borne on flowering stems (scapes) without leaves. Aiken and LeBlanc 04–009. CAN 586481. • Close-up of plant. Plants with most leaves close to the ground and flowers borne on flowering stems (scapes) without leaves. Aiken and LeBlanc 04–009. CAN 586481. • Habitat. Plants growing in sand of a creek bed. Nunavut, Victoria Island, Cambridge Bay. Photograph by Laurie Consaul. No voucher. • Albino and coloured plants. Left, an albino plant. Right, a coloured plant growing side by side. Aiken and LeBlanc 04–009. CAN 586481. • Close-up of albino plant. Albino plant with basal leaves. Flowers with pale yellow green sepals and white petals without any pale pink colouration. Note the yellow green as opposed to purplish red gynoecia. Aiken and LeBlanc 04–009. CAN 586481. • Plant with smaller leaves. Plant growing in wave washed gravel on the drift edge of a lake. Note very small leaves. Nunavut, Baffin Island, Ogac Lake. Aiken and LeBlanc 04–072. CAN 586540. • Close-up of plant. Plant in flowering stage in snowbed. Note 'tussocky' growth. There are no rhizomes such as in S. rivularis. Norway, Svalbard, Sassen, Noisdalen. 5 July, 1987. Photograph by R. Elven. Voucher at 0. • Close-up of flowers. Note pink stripe on petals, exserted anthers and stigmas, and a fly on one of the upper flowers. Norway, Svalbard, Noisdalen. 5 August, 1987. Photograph by R. Elven. Voucher at 0. • Arctic Island Distribution.