Flora of the Canadian Arctic Archipelago
Saxifragaceae, Saxifrage family.
Published in Sp. Pl. 398.1753.
Vegetative morphology. Plants 1–15(–35) cm high; perennial herbs; caespitose, or not caespitose; sometimes vegetatively proliferating by bulbils on stems or leaves, or sometimes vegetatively proliferating in inflorescences, or never vegetatively proliferating by bulbils on stems or leaves, in inflorescences, from gemmiphores and gemmae, or by fragmentation. Taproot present (rarely), or only fibrous roots present. Ground level or underground stems horizontal, or absent (usually), or vertical; stoloniferous (S. flagellaris), or rhizomatous (S. rivularis); elongate, or compact. Horizontal stems at ground level, branching extensively to shape plant habit as mats, or cushions. Caudex present, or absent. Aerial stems erect, or decumbent, or prostrate. Leaves heterophyllous, or not heterophyllous; mainly basal, or distributed along the stems; patent, or erect; alternate (usually), or opposite; persistent, or dying annually and non-persistent, or marcescent. Petioles absent, or present; 0–25(–50) mm long; glabrous, or hairy; puberulent, or pubescent, or pilose, or villous. Petiole hairs shorter than the diameter of the petiole, or longer than the diameter of the petiole. Leaf blades simple. Leaf blade bases cordate, or truncate, or obtuse, or cuneate, or attenuate, or rounded, or hastate. Blades 2–20(–70) mm long, 0.4–10(–35) mm wide, appressed to the stem or spreading, linear or oblong or elliptic or lanceolate or ovate or oblanceolate or obovate or spatulate or reniform or triangular, flat, veins palmate (S. cernua) or appearing single-veined or with inconspicuous veins. Blade adaxial surface glabrous or hairy, hairs puberulent, hairs simple or glandular, hairs sparse, hairs white, or translucent (if applicable). Blade abaxial surface glabrous or hairy, hairs puberulent or pilose or villous, hairs sparse or moderately dense, hairs white or a mixture of white and rust-coloured. Blades lobed or not lobed. Blade margins entire or glandular-dotted or serrulate or serrate or crenate or deeply divided, with 7–10 glands per cm, with non-glandular hairs or glabrous or with glandular hairs, with 3–7 teeth on each side of the blade, with teeth toward the apex; degree of incision 50–70%. Hydathodes present and conspicuous, or present but inconspicuous, or absent. Blade apices acute, or obtuse, or acuminate, or rounded.
Reproductive morphology. Plants monoecious (rarely S. eschscholtzii), or bisexual. Flowering stems about as high as the leaves, or conspicuously taller than the leaves; without leaves, or with leaves. Flowering stems hairy. Flowering stems pubescent, or pilose, or villous, or woolly. Flowering stem hairs simple, or branched; shorter than the diameter of the flowering stem, or longer than the diameter of the flowering stem; white or translucent, or brown, or yellow, or transparent with deep purple cross-walls; glandular hairs present, or absent. Flowers solitary, or in inflorescences. Inflorescences with bulbils, or without bulbils; spicate, or racemose, or paniculate, or cymose, or head-like; (0–)1–10 cm long. Pedicels present, or absent; with non-glandular hairs, or with glandular hairs, or with sessile glands (if applicable). Flowers per inflorescence 1–15(–20); small, or medium-sized; radially symmetrical (actinomorphic); unisexual, or bisexual. Sepals conventional; 5; free; (0.5–)1–2.6 mm long; (1–)2–5.5 mm wide; green, or purple, or red; herbaceous, or scarious. Calyx hairy, or glabrous. Calyx hairs pilose; glandular, or non-glandular; white or translucent, or brown. Calyx margins ciliate, or margins without cilia. Petals conventional; free; shorter than the calyx, or same length as the calyx, or longer than the calyx; 5; green, or white, or yellow, or red, or pink, or purple; with contrasting markings, or without contrasting markings; elliptic, or ovate, or obovate, or spatulate; unlobed; 1–7(–15) mm long; (0.4–)1–4 mm wide. Stamens 10; stamen filaments glabrous; free of the corolla. Anthers purple, or purple becoming yellow, or yellow; short-cylindrical, or ovoid, or sub-globose; 0.2–0.9 mm long. Nectaries present. Receptacle 0.1–7 mm high. Ovary superior, or partly inferior, or inferior; carpels 2; partly fused. Ovaries glabrous. Placentation axile. Ovules per ovary 10–100 (many). Fruit with calyx persisting; dry; a capsule; spherical, or ellipsoid, or ovoid, or elongate-cylindrical, or urceolate; brown, or red, or purple, or golden brown, or straw-coloured; 2.5–12 mm long (mean 5.8 mm); 2–7 mm wide (mean 4.5 mm); hairy, or glabrous; dehiscent; splitting to the base into separate segments. Seeds 10–100 (many); 0.4–1.5 mm long; black, or brown, or yellowish; surfaces smooth, hairy, verrucose, ridged, winged.
North American distribution. Range in the Canadian Arctic Archipelago widespread. Common, rare, uncommon. Arctic, alpine (and boreal).
General notes. Elven et al. (2003) noted that variation within the genus Saxifraga in Arctic floras needs special investigation.
Considerable isolation of some sections has been the basis for repeatedly considering them as independent genera (Haworth 1812, 1821, Small 1905, Rydberg 1932). The modular character of the genus is partly confirmed by modern genetic investigations (Brochman et al. 1996).
Conti et al. (1999) discussed phylogenetic relationships of the silver saxifrages (Saxifraga, sect. Ligulatae Haworth) and implications for the evolution of substrate specificity, life histories, and biogeography.
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..