Saxifragaceae – Saxifrage Family
Latin for “rock breaking” the Saxifragaceae are a collection of perennial herbaceous plants with about 600 known species in 30 to 33 accepted genera.[i] Widely distributed across the Northern Hemisphere, the world’s greatest center of Saxifragaceae diversity is found in the Pacific Northwest. Occupying a range of ecosystems, members of this family can be found growing anywhere in Oregon from dry lava beds, to shady conifer forests, to saturated riparian woodlands, and sun drenched wetland prairies.[ii]
Leaves are simple, usually basal but sometimes arranged in an alternate pattern. Different genera in our area have very dissimilar shaped leaves. For example, many in the genera Saxifraga have leathery, basal, and somewhat succulent leaf blades. They are usually pinnately veined and can be oblong, lance-like, spoon-like, wedge shaped, or oval, and almost all have distinctly toothed margins, although some are entire.[iii] Members of the Heuchera genera, in contrast have many basally arranged soft, hairy, lobed deciduous leaves with palmate veins.
Saxifragaceae inflorescences are crowded or open panicles at the end of a long stalk. Flowers are typically small, radially symmetric, and usually have five fused sepals surrounding five distinct petals.[iv] There are five or ten stamens and ovaries are often superior with two united carpels that form an oblong chamber. Ovaries mature into dry capsules and release numerous tiny seeds.[v]
Several members of this family are valued by gardeners interested in using native plants adapted for shady habitats. Astilbe is a genus of rhizomatous North American plants cultivated for their large fern-like leaves and bright pink or white feathery inflorescence spikes. Ranging from chartreuse, to pink, to deep purples, Heuchera (coral bells) is another commonly hybridized ornamental valued for colorful foliage and dramatic variegation as well as shade tolerance.
Saxifraga oregana – Bog Saxifrage (Marsh Saxifrage)
Species Code: SAOR
Growth Habit: Rhizomatous perennial forb with long, hairy, sticky inflorescence scape emerging from rosette of sessile basal leaves.
Leaves: Oval shaped, smooth leaves are fleshy/succulent like and all basal. Leaves are sessile and can be 7 to 25 cm long, tapered at the base, with smooth to serrated margins.[vi]
Flowers: Inflorescence scape seems to grow directly from the rhizome rising 30 to 120 cm tall, ending in crowded or open to panicles at the stalk’s end.[vii] A leaf-like bract is present where pedicles branch off of the central inflorescence stalk (scape), which is quite sticky closer to the plant’s top due to glandular hairs along the scape. Flowers have five small, greenish white petals that are 2 to 4 mm long.[viii]
Fruits: Its flowers dry, leaving brown capsules at the top of the plant. The seed is ready for collection when the capsules release many tiny brown seeds. The tiny seeds are 0.8- 1.2 mm long, slightly larger than the seeds of Juncus species (Hitchcock et al. 1955-69).
Ecology: FACW+ Wet meadows.
Notes: May be confused with: Swamp saxifrage (S. integrifolia), which has relatively long petioles and a single, head-like cluster of flowers; Rusty hair saxifrage (S. ferruginea) which has oval leaves with coarse, sharp margins.[ix]
[i] Simpson, M. Plant Systematics 2nd ed. Academic Press, Burlington, MA. 2010. 391
[ii] Pojar, J., Mackinnon, A., Editors Plants of the Pacific Northwest Coast. Lone Pine Publishing, Vancouver, Canada. 2004. 158.
[iii] Pojar, J., Mackinnon, A., Editors Plants of the Pacific Northwest Coast. Lone Pine Publishing, Vancouver, Canada. 2004. 158-162.
[iv] Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001. 189.
[v] Elpel, T. J., Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, 2004. 86.
[vi] Guard, J. Wetland Plants of Oregon and Washington. Lone Pine Publishing, Edmonton, Alberta. 1995. 108.
[vii] Pojar, J., Mackinnon, A., Editors Plants of the Pacific Northwest Coast. Lone Pine Publishing, Vancouver, Canada. 2004.
[viii] Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001. 199.
[ix] City of Eugene, Parks Seed Collection Manual, Saxifraga oregana, 2009.