Saxifraga L.
Saxifragaceae, saxifrage family.
Sp. Pl. 398. 1753
Type: Sp. Pl. 398.1753.
Vegetative morphology. Plants perennial herbs; 1–30 cm high (mean 11 cm); caespitose, or not caespitose; with single unbranched stems, or with erect unbranched stems arising close together, or cushion-like, or with branched or unbranched matted stems, or with unbranched stems arising from a basal rosette of leaves; vegetatively proliferating by bulbils or fragmentation, or not vegetatively proliferating by bulbils or fragmentation. Taproot present (rarely), or absent. Caudex present, or absent. Ground-level or under-ground stems horizontal, or not developed horizontally or vertically (usually); stoloniferous (S. flagellaris), or rhizomatous (S. rivularis); elongate, or compact. Aerial stems erect, or decumbent; glabrous, or sparsely hairy, or densely hairy. Leaves heterophyllous, or not heterophyllous; basal in a rosette, or in a basal tuft, or distributed along the stems; alternate, or opposite; simple; evergreen, or existing for a single season or less, or marcescent. Petioles absent, or present; 0–50 mm long (mean 17 mm); glabrous, or hairy; puberulent, or pilose, or villous; hairs less than the diameter of the petiole, or hairs more than the diameter of the petiole. Leaf blade bases cordate, or obtuse, or acute, or cuneate, or attenuate. Blades 2–70 mm long (mean 13 mm); 0.4–35 mm wide (mean 7 mm). Blades herbaceous, or leathery, or succulent; elliptic, or linear, or lanceolate, or oblanceolate, or oblong, or ovate, or obovate, or circular, or spatulate, or reniform; flat; veins palmate (S. cernua), or appearing single-veined, or with inconspicuous veins. Blades adaxial surface glabrous, or hairy. Blades abaxial surface glabrous, or hairy. Blade margins lobed, or not lobed. Blade margins with non-glandular hairs, or glabrous. Conspicuous hydathodes present, or absent. Leaf apices acute, or obtuse, or acuminate, or rounded.
Reproductive morphology. Plants monoecious (rarely S. eschscholtzii), or bisexual. Flowering stems present. Flowering stems without leaves, or with leaves; hairy, or glabrous. Flowers solitary, or in inflorescences. Inflorescence spicate, or racemose, or paniculate, or cymose, or head-like; terminal, or axillary; 0–3 cm long (mean 1.3 mm); with bulbils, or without bulbils. Pedicels present, or absent. Involucral bracts absent. Flowers per inflorescence 1–15; small, less than 5 mm in diameter or length, or medium-sized, 5–15 mm in diameter or length; actinomorphic. Calyx present. Calyx sepals 5; free. Calyx green, or purple, or red; herbaceous, or scarious; hairy, or glabrous. Petals free; 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 lanceolate, or oblanceolate, or spatulate; unlobed; 1–12 mm long (mean 5.2 mm). Flowers unisexual, or bisexual. Stamens 10; filaments all equal in length; free of the corolla. Nectaries present. Gynoecia superior, or partly inferior. Carpels partly fused; 2. Ovaries glabrous, or hairy. Styles absent, or present; 2; free. Stigmas per style 1. Placentation axile. Ovules 10–100. Fruit with calyx persisting, or without calyx persisting; dry; a capsule; spherical, or ellipsoid, or ovoid; dehiscent; splitting to the base into separate segments. Fruit 2.5–12 mm long (mean 5.8 mm); 2–7 mm wide (mean 4.5 mm); black, or brown, or purple, or green at maturity; hairy, or glabrous. Seeds 10–100; 0.5–1.5 mm long (mean 9.5 mm); brown; with surfaces smooth, or verrucose, or ridged, or winged.
Distribution. Northern hemisphere distribution: circumpolar, or amphi-Atlantic, or amphi-Beringian, or North American. Arctic, or alpine (and boreal). Range in the Canadian Arctic Archipelago widespread. Common, or rare, or uncommon.
Notes. Species variation of genus Saxifraga in Arctic flora
needs special investigation and discussion. First of all, the taxonomic status
of races in such polymorphic taxa as S. cespitosa s. lat. or S.
rivularis s. lat. is not clear. In such cases we consider the generally
accepted viewpoint as priority. On the other hand significant difference in some
species interpretation, such as S. bronchialis or S. davurica, is
related not only to the acceptance of different species concepts but also to the
traditional volume of the taxon. In these cases different viewpoints are taken
into account and taxa are lumped into polymorphic complexes (aggregates).
(Zhmylev in discussion for Elven et al. 2003)
Considerable isolation of some
sections has been the basis for repeatedly considering them as independent
genera (Haworth 1812, 1821, Small 1905, Rydberg 1965, Löve 1983, etc.). The
modular character of the genus is partly confirmed by modern genetic
investigations (Soltis et al. 1996). Currently the majority of botanists
consider genus Saxifraga s. lat. in a broad sense. Following this
tradition its numerous sections are grouped into subgenera.
Species
variation of genus Saxifraga in Arctic flora needs special investigation
and discussion. First of all, the taxonomic status of races in such polymorphic
taxa as S. cespitosa s. lat. or S. rivularis s. lat. is not clear.
In such cases we consider the generally accepted viewpoint as priority. On the
other hand significant difference in some species interpretation, such as S.
bronchialis or S. davurica, is related not only to the acceptance of
different species concepts but also to the traditional volume of the taxon. In
these cases different viewpoints are taken into account and taxa are lumped into
polymorphic complexes (aggregates). (Zhmylev).
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).