The common caltha palustris, or "marsh marigold" of England, which is not found in Sikkim, is very abundant in the north-west Himalaya.
"Himalayan Journals V2."
J. D. Hooker
The caltha is common to both Europe and America and, though it is often hereabout known by the nickname of "cowslip" which the early English settlers seem to have given it, I do not hear it called mayflower.
"Old Plymouth Trails"
Winthrop Packard
Whoever has seen the watery Avon meadows in April, yellow and twinkling with marsh marigolds when "the lark at heaven's gate sings," appreciates why the commentators incline to identify Shakespeare's Mary-buds with the caltha of these and our own marshes.
"Wild Flowers Worth Knowing"
Neltje Blanchan et al