The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

ascending saxifrage, rock saxifrage, wedge-leaf saxifrage

brook saxifrage, pygmy saxifrage, saxifrage hyperboréale

Habit Plants biennial, sometimes behaving as winter annual, solitary or tufted, not stoloniferous, with caudex. Plants solitary or in compact, or sometimes loose, tufts, (usually wholly purple, sometimes green), not stoloniferous, not rhizomatous, with caudex.
Leaves

basal and cauline, (basal persistent, compact);

petiole absent (cuneate base ± petiolelike);

blade oblanceolate to obovate, (2–)3(–5)-toothed or shallowly lobed apically, rarely unlobed (distal often so), (lobes forwardly directed), (2–)4–15 mm, slightly fleshy, margins entire, stipitate glandular-ciliate, apex obtuse, surfaces glabrate to stipitate-glandular.

basal and cauline, (cauline 1–3, dissimilar from basal, reduced);

petiole ± flattened, (2–)5–35 mm;

blade reniform to orbiculate, (2–)3–5(–7)-lobed (lobes rounded), (2–)3–6(–10) mm, thin or slightly fleshy, margins entire, eciliate or sparsely stipitate-glandular, (inconspicuous nonsecreting hydathodes sometimes present), apex acute, surfaces glabrous or sparsely hairy.

Inflorescences

(2–)6–15(–40)-flowered thyrses, (1–)4–25 cm, densely purple-tipped stipitate-glandular;

bracts sessile.

2–5-flowered cymes, sometimes solitary flowers, 1–5 cm, tangled, purple-tipped stipitate-glandular;

bracts petiolate.

Flowers

sepals erect, (usually reddish purple), ovate or triangular to oblong, margins stipitate glandular-ciliate, surfaces stipitate-glandular;

petals white, not spotted, obovate to oblanceolate, (2–)3–6 mm, equaling or longer than sepals;

ovary inferior.

(hypanthium U-shaped in longisection, sparsely to densely long stipitate-glandular);

sepals erect, (sometimes purple), ovate to lance-oblong, (1.5–2.1 mm wide), margins eciliate, surfaces ± stipitate-glandular;

petals purple or white, often midvein ± purplish, faded when dried, not spotted, oblong, (1.5–)2–3.4(–5) mm, equaling or to 1.5 times sepals;

ovary 1/2 inferior.

2n

= 22.

= 26.

Saxifraga adscendens

Saxifraga hyperborea

Phenology Flowering summer. Flowering summer.
Habitat Moist, often shaded cliff ledges, screes, talus slopes, gravelly stream banks, gravelly alpine meadows Wet tundra, open gravel and silt, stream and lake margins, snow beds, shady ravines and cliffs, seepage under rocks, silty and gravelly seashores
Elevation 1200-4200 m (3900-13800 ft) 0-3000+ m (0-9800+ ft)
Distribution
from FNA
AK; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC; NT; YT; Europe
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AZ; CA; CO; ID; MT; OR; WA; WY; AB; BC; LB; MB; NT; NU; QC; YT; Greenland; n Asia; Atlantic Islands (Spitsbergen)
[WildflowerSearch map]
[BONAP county map]
Discussion

Although the North American plants of Saxifraga adscendens have been known as subsp. oregonensis, expressions of the supposed distinguishing characters appear to overlap completely with the variation found in Europe. The plants produce bulbils on caudices.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Reports of Saxifraga hyperborea from Mount Washington, New Hampshire (e.g., Á. Löve and D. Löve 1964) require confirmation; all specimens examined from this location appear to be S. rivularis. C. L. Hitchcock (1961) treated all western material as S. debilis, including that of the Pacific Northwest that is included here. For Colorado, W. A. Weber (1990) appears to have applied the name S. rivularis to what we call S. hyperborea, and S. hyperborea subsp. debilis to what we call S. debilis. P. K. Holmgren and N. H. Holmgren (1997) included under their broad concept of S. rivularis both S. hyperborea and S. debilis, noting that the plants had gone usually under the latter name. Both species are present in the Rockies and the Intermountain Region.

In northeastern North America, Saxifraga hyperborea and S. rivularis are often sympatric, although the latter is absent from the extreme north. The major distinguishing feature between diploid S. hyperborea and tetraploid S. rivularis is the presence of rhizomes in the former and their absence in the latter (see key), a character that is sometimes difficult to interpret on herbarium sheets. Plants of S. hyperborea are usually smaller (2–5 cm) and reddish (sometimes green), with usually three- to five-lobed leaves and petals about one and one-half times longer than sepals, while plants of S. rivularis are taller (5–10 cm) and usually green (although sometimes reddish, particularly in the western var. arctolitoralis), with usually five-lobed leaves and petals two to three times longer than sepals.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 8, p. 145. FNA vol. 8, p. 144.
Parent taxa Saxifragaceae > Saxifraga Saxifragaceae > Saxifraga
Sibling taxa
S. aizoides, S. aleutica, S. bracteata, S. bronchialis, S. cernua, S. cespitosa, S. cherlerioides, S. chrysantha, S. debilis, S. eschscholtzii, S. flagellaris, S. hirculus, S. hyperborea, S. mertensiana, S. nathorstii, S. oppositifolia, S. paniculata, S. radiata, S. rivularis, S. serpyllifolia, S. taylorii, S. tricuspidata, S. tridactylites, S. vespertina
S. adscendens, S. aizoides, S. aleutica, S. bracteata, S. bronchialis, S. cernua, S. cespitosa, S. cherlerioides, S. chrysantha, S. debilis, S. eschscholtzii, S. flagellaris, S. hirculus, S. mertensiana, S. nathorstii, S. oppositifolia, S. paniculata, S. radiata, S. rivularis, S. serpyllifolia, S. taylorii, S. tricuspidata, S. tridactylites, S. vespertina
Synonyms Muscaria adscendens, S. adscendens subsp. oregonensis, S. adscendens var. oregonensis, S. oregonensis S. flexuosa, S. rivularis var. flexuosa, S. rivularis subsp. hyperborea, S. rivularis var. hyperborea, S. rivularis var. purpurascens
Name authority Linnaeus: Sp. Pl. 1: 405. 1753 , R. Brown: Chlor. Melvill., 16. 1823 ,
Web links