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Threeleaf Foamflower (Tiarella trifoliata)
Genus Tiarella Family Saxifragaceae Order Rosales Class Magnoliopsida Phylum Tracheophyta Kingdom Plantae Biodiversity

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Source: Wikipedia

Tiarella trifoliata
Mount Baker-Snoqualmie National Forest, State of Washington, USA (23 June)

Secure  (NatureServe)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Saxifragaceae
Genus: Tiarella
Species:
T. trifoliata
Binomial name
Tiarella trifoliata
Synonyms[3][4][5]
T. trifoliata var. laciniata
    • Tiarella laciniata Hook.
    • Heuchera californica Kellogg
    • Tiarella californica (Kellogg) Rydb.
T. trifoliata var. trifoliata
    • Blondia trifoliata Raf.
    • Petalosteira laciniata Raf.
    • Tiarella stenopetala C.Presl
    • Tiarella trifolia J.F.Gmel.
T. trifoliata var. unifoliata
    • Petalosteira unifolia (Hook.) Raf.
    • Tiarella trifoliata subsp. unifoliata (Hook.) P.M.Kern
    • Tiarella unifoliata Hook.
    • Tiarella unifoliata f. typica Lakela
    • Tiarella unifoliata f. trisecta Lakela
Salmon-Huckleberry Wilderness, Mount Hood National Forest, Oregon, USA (23 August)

Tiarella trifoliata, the three-leaf foamflower, is a species of flowering plant in the family Saxifragaceae.[6] The specific name trifoliata means "having three leaflets",[7] a characteristic of two of the three recognized varieties. Also known as the laceflower or sugar-scoop,[8] the species is found in shaded, moist woods in western North America.

Description

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Tiarella trifoliata is a perennial dicotyledonous herb that flowers in the late spring. The flowers are bell-shaped, white and solitary forming an elongated, leafless panicle. The calyx lobes are 1.5–2.5 mm and petals are 3–4 mm. Basal leaves are 15–80 mm long and up to 120 mm wide, trifoliate or palmately 3- to 5-lobed. Cauline leaves are infrequent and much smaller.[9]

The typical variety of Tiarella trifoliata (var. trifoliata) has petiolate leaves with three leaflets per leaf (i.e., trifoliate). The cut-leaved foamflower (var. laciniata) also has trifoliate leaves with petioles, but unlike the typical variety, it has deep lobes more than half the length of the leaflet. The one-leaf foamflower (var. unifoliata) has sessile, simple leaves (rarely trifoliate).[6]

Taxonomy

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Tiarella trifoliata was first described by the Swedish botanist Carl Linnaeus in 1753.[2] Its type specimen was collected by Georg Steller on Cape St. Elias, Kayak Island, Alaska in 1742, but that specimen is now lost. A specimen collected from Sitka, Alaska has been designated as the neotype for this species.[10]

In 1832, William Hooker described two additional species of Tiarella in western North America (T. laciniata and T. unifoliata),[11][12] including two hand-drawn illustrations in his description.[13][14] John Torrey and Asa Gray recognized all three species (T. trifoliata, T. laciniata, T. unifoliata) in their treatment of genus Tiarella in 1840.[15]

In 1905, Per Axel Rydberg described T. californica based on an earlier description of a species thought to belong to genus Heuchera.[16] All four species (T. trifoliata, T. laciniata, T. unifoliata, T. californica) were included in a taxonomy proposed by Olga Lakela in 1937.[17]

Based on Hooker's species description, William Efner Wheelock renamed T. laciniata Hook. as a variety of Tiarella trifoliata (var. laciniata) in 1896.[18] Similarly, Federico Kurtz renamed T. unifoliata Hook. as Tiarella trifoliata var. unifoliata in 1894.[19] Flora of North America recognized the varieties (var. laciniata and var. unifoliata) in an influential treatment of genus Tiarella published in 2009.[20] As of October 2022, the varieties (not the species) are widely recognized:[6][21][22][1][23][24][25]

  • Tiarella trifoliata L.
    • Tiarella trifoliata var. laciniata (Hook.) Wheelock (synonym: T. laciniata Hook.)
    • Tiarella trifoliata var. trifoliata
    • Tiarella trifoliata var. unifoliata (Hook.) Kurtz (synonym: T. unifoliata Hook.)

Likewise Tiarella californica (Kellogg) Rydb. is considered to be a synonym of T, trifoliata var. laciniata.

Distribution

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In western North America, Tiarella trifoliata prefers shaded, moist, sometimes dense woods up to 1,900 m (6,234 ft).[6] It ranges from northern California through western Canada northward to Alaska, and eastward to Montana.[22][26][27] Within this region, the varieties of T. trifoliata have overlapping ranges:

  • Tiarella trifoliata var. laciniata:[3] British Columbia; Oregon, Washington
  • Tiarella trifoliata var. trifoliata:[4] Alberta, British Columbia; Alaska, California, Idaho, Montana, Oregon, Washington
  • Tiarella trifoliata var. unifoliata:[5] Alberta, British Columbia; Alaska, California, Idaho, Montana, Oregon, Washington

T. trifoliata var. trifoliata and T. trifoliata var. unifoliata range north to Alaska, while T. trifoliata var. laciniata only ranges as far north as Vancouver Island in British Columbia.[28]

Conservation

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The conservation status of Tiarella trifoliata is globally secure (G5).[1] Each variety is secure as well.

References

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  1. ^ a b c "Tiarella trifoliata". NatureServe Explorer. NatureServe. Retrieved 15 November 2022.
  2. ^ a b "Tiarella trifoliata L.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 7 October 2022.
  3. ^ a b "Tiarella trifoliata var. laciniata (Hook.) Wheelock". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 14 November 2022.
  4. ^ a b "Tiarella trifoliata var. trifoliata". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 14 November 2022.
  5. ^ a b "Tiarella trifoliata var. unifoliata (Hook.) Kurtz". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 14 November 2022.
  6. ^ a b c d Jog, Suneeti (2009). "Tiarella trifoliata". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 8. New York and Oxford: Oxford University Press – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  7. ^ Gledhill, David (2008). The Names of Plants (4th ed.). Cambridge University Press. p. 386. ISBN 978-0-521-86645-3.
  8. ^ "Tiarella trifoliata". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 27 October 2022.
  9. ^ Giblin, David. "Tiarella trifoliata". Burke Herbarium Image Collection. University of Washington. Retrieved 27 October 2022.
  10. ^ Reveal, James L. (1991). "Typification of the Linnaean species of Tiarella (Saxifragaceae)". Phytologia. 71 (6): 479–482. Retrieved 12 October 2022.
  11. ^ "Tiarella laciniata Hook.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 7 October 2022.
  12. ^ "Tiarella unifoliata Hook.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 7 October 2022.
  13. ^ Hooker, William Jackson (1840). "Plate 77: Tiarella laciniata". Flora Boreali-Americana. 1 (5). London. Retrieved 12 October 2022.
  14. ^ Hooker, William Jackson (1840). "Plate 81: Tiarella unifoliata". Flora Boreali-Americana. 1 (5). London. Retrieved 12 October 2022.
  15. ^ Torrey & Gray (1840), pp. 587–588.
  16. ^ "Tiarella californica (Kellogg) Rydb.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 24 October 2022.
  17. ^ Lakela (1937).
  18. ^ "Tiarella trifoliata var. laciniata (Hook.) Wheelock". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 9 October 2022.
  19. ^ "Tiarella trifoliata var. unifoliata (Hook.) Kurtz". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 9 October 2022.
  20. ^ Jog, Suneeti (2009). "Tiarella". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 8. New York and Oxford: Oxford University Press – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  21. ^ USDA, NRCS (n.d.). "​Tiarella trifoliata​". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 12 October 2022.
  22. ^ a b "Tiarella trifoliata L.". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 14 November 2022.
  23. ^ "Tiarella trifoliata L.". Integrated Taxonomic Information System (ITIS). Retrieved 7 October 2022.
  24. ^ "WFO (2022): Tiarella trifoliata L.". The World Flora Online. Retrieved 9 October 2022.
  25. ^ "Tiarella trifoliata L.". E-Flora BC: Electronic Atlas of the Plants of British Columbia. 2020. Retrieved 9 October 2022.
  26. ^ "Tiarella trifoliata". State-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014. Retrieved 11 October 2022.
  27. ^ "Tiarella trifoliata". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014. Retrieved 2 November 2022.
  28. ^ Pojar, Jim; MacKinnon, Andy. Plants of the Pacific Northwest Coast. Lone Pine Publishing, 1994, p. 168, ISBN 978-1-55105-040-9

Bibliography

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About

First documented in July 2023 in Santa Cruz County, California.