Caltha palustris (Kingcup or Marsh Marigold) is a member of the family Ranunculaceae, and is native to temperate regions of the Northern Hemisphere, growing in wet, boggy places.

It is a herbaceous perennial plant 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. The flowers are yellow, 2-5 cm diameter, with 4-9 (mostly 5) petaloid sepals; they are borne in early spring to late summer.

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.

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.

Other names and etymology

It is also occasionally known as may blobs, or cowslip (although it should not be confused with Primula veris, which also goes by that name).

The common name of marigold refers to its use in Churches in medieval times at Easter time as a tribute to the Virgin Mary, as in Mary gold. In parts of the UK in the 19th century, the plant was called Mayblob, possibly derived from Mereblob or more likely from Marybud. The specific name palustris, from Latin "of a marsh", indicates its common habitat.

It is a plant commonly mentioned in literature, including Shakespeare:

Winking Marybuds begin

To open their golden eyes (Cymbeline, ii. 3).

External links

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• Germplasm Resources Information Network: Caltha palustris

Ranunculaceae | Flora of North America

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