Photographed just around the bend on my road, Ste. Rita, Manitoba.
Canon EOS Digital Rebel XTi; 17-85mm lens
Featured in Wildflowers of North America – October 15, 2009
Featured in Endangered Plants – June 12, 2009
Caltha palustris commonly known as Kingcup or Marsh Marigold belongs to the Ranunculaceae (buttercup family). It is native to temperate regions of the Northern Hemisphere (Europe including Iceland and Arctic Russia, temperate and Arctic Asia, and North America). It grows in wet, boggy places, such as marshes, fens, ditches and wet woods. It becomes most luxuriant in partial shade, but is rare on peat. In the UK, it is probably one of the most ancient British native plants, surviving the glaciations and flourishing after the last retreat of the ice, in a landscape inundated with glacial meltwaters.
The plant is a herbaceous perennial growing to 80 cm tall. The leaves are rounded to kidney-shaped, 3-20 cm across, with a bluntly serrated margin and a thick, waxy texture. Stems are hollow. The flowers are yellow, 2-5 cm diameter, with 4-9 (mostly 5) petaloid sepals and many yellow stamens; they are borne in early spring to late summer. The flowers are visited by a great variety of insects for pollen and for the nectar secreted from small depressions, one on each side of each carpel. Carpels form into green sac-like follicles to 1cm long, each opening to release several seeds. It flowers early April and May and is very valuable to insects at this time as they provide nectar and pollen to them.
Caltha palustris is a highly polymorphic species, showing continuous and independent variation in many features. Forms in the UK may be divided into two subspecies: Caltha palustris subsp. palustris, and Caltha palustris subsp. minor.
It is sometimes considered a weed in clayey garden soils, where every piece of its root will survive and spread. In warm free-draining soils, it simply dies away.
Caltha palustris flowers
As is the case with many members of the Ranunculaceae, all parts of the plant can be irritant or poisonous. Skin rashes and dermatitis have been reported from excessive handling of the plant.
Marsh-marigolds are in decline as agricultural land continues to be drained.
[Assessed on the internet June 6, 2009]