Micranthes pensylvanica (Linnaeus) Haworth. Section: Micranthes. Common name: Swamp Saxifrage. Phenology: Apr-Jun. Habitat: Forested seeps and seepage swamps, fens, usually over mafic or calcareous rocks. Distribution: ME west to MN, south to e. VA, c. and w. NC, and IA.
Origin/Endemic status: Native
Taxonomy Comments: Haines (2024c) followed earlier authors in recognizing multiple infrataxa in Micranthes pensylvanica (see synonymy); these need additional study. In our region, we have two of his entities, var. pensylvanica and var. purpuripetala. Var. pensylvanica has petals greenish white, mostly 3-4 mm long and 0.5-0.7 mm wide, leaf blades hirsute on one or both surfaces, and filaments of the stamens white to pale brown. Var. purpuripetala (known from PA) has petals reddish purple to purple, mostly 2-3 mm long and 0.3-0.5 mm wide, leaf blades more-or-less glabrous, and filaments of the stamens purple or tinged with purple.
Synonymy ⓘ: = Il, Mi; = n/a — S, S13; = Saxifraga pensylvanica L. — F; = Saxifraga pensylvanica L. ssp. pensylvanica — G; > Micranthes apetala (Piper) Small; < Micranthes pensylvanica (L.) Haw. — Can, FNA8, K4, NE, NY, Tn, Va, Brouillet & Gornall (2007), Tkach, Röser, & Hoffmann (2015); > Micranthes pensylvanica (L.) Haw. ssp. crassicarpa (A.M. Johnson) A. Haines var. crassicarpa — Haines (2024c); > Micranthes pensylvanica (L.) Haw. ssp. crassicarpa (A.M. Johnson) A. Haines var. winnebagoensis (A.M. Johnson) Bush — Haines (2024c); > Micranthes pensylvanica (L.) Haw. ssp. pensylvanica var. pensylvanica — Haines (2024c); > Micranthes pensylvanica (L.) Haw. ssp. pensylvanica var. purpuripetala (A.M. Johnson) Bush — Haines (2024c); > Micranthes pensylvanica (L.) Haw. ssp. tenuirostra (Burns) A. Haines — Haines (2024c); < Saxifraga pensylvanica L. — C, Pa, RAB, Tat, W, WV; > Saxifraga pensylvanica L. ssp. eupensylvanica Burns, illegitimate name; > Saxifraga pensylvanica L. ssp. eupensylvanica var. purpuripetala (Johnson) Bush. Basionym: Saxifraga pensylvanica L. 1753
Links to other floras: < Micranthes pensylvanica - FNA8
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Wetland Indicator Status:
- Atlantic and Gulf Coastal Plain: OBL
- Eastern Mountains and Piedmont: OBL (taxonomic split from wetland indicator species)
- Great Plains: FACW (taxonomic split from wetland indicator species)
- Midwest: OBL (taxonomic split from wetland indicator species)
- Northcentral & Northeast: OBL (taxonomic split from wetland indicator species)
Heliophily ⓘ: 4
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© Gary P. Fleming | Original Image ⭷
© Gary P. Fleming | Original Image ⭷
© Erik Danielson source | Original Image ⭷
© Erik Danielson source | Original Image ⭷
© Scott Ward | Original Image ⭷
© Erik Danielson source | Original Image ⭷Feedback
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Horticultural Information
Intro: Erect, rosette-forming perennial of forested seeps and seepage swamps and fens, usually over mafic or calcareous rocks.
Stems: Flowering stems stout, branched above in inflorescence, densely sticky-hairy.
Leaves: Leaves basal, short-petiolate, elliptic to lance-shaped and tapering at the base, 4-10 in. long, shallowly toothed, with conspicuous midrib, sparsely hairy or smooth.
Inforescence:
Flowers: Flowers in a dense panicle that elongates and loosens with age, bracts subtending the sticky-hairy branches; white to yellow or greenish-purple; 1/8-1/4 in. wide; consisting of 5 minute lance-shaped petals, 10 thin orange-tipped stamens and a 2-lobed conical ovary.
Fruits: Fruit a 2-lobed, pointed oval capsule, the 2 sections widely spreading at maturity.
Comments:
Height: 11-30 in..
plant sale text:
bloom table text:
description: Erect, rosette-forming perennial of forested seeps and seepage swamps and fens, usually over mafic or calcareous rocks.
stems: Flowering stems stout, branched above in inflorescence, densely sticky-hairy.
leaves: Leaves basal, short-petiolate, elliptic to lance-shaped and tapering at the base, 4-10 in. long, shallowly toothed, with conspicuous midrib, sparsely hairy or smooth.
inflorescence:
flowers: Flowers in a dense panicle that elongates and loosens with age, bracts subtending the sticky-hairy branches; white to yellow or greenish-purple; 1/8-1/4 in. wide; consisting of 5 minute lance-shaped petals, 10 thin orange-tipped stamens and a 2-lobed conical ovary.
fruits: Fruit a 2-lobed, pointed oval capsule, the 2 sections widely spreading at maturity.
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