Definition of "nasturtian"

ASPARAGUS, cauliflowers, imperial Sileſia, royal and cabbage lettuces, burnet, purſlain, cucumbers, naſturtian flowers, peaſe and beans ſown in October, artichokes, ſcarlet ſtrawberries, and kidney beans.

1767, A Lady [Hannah Glasse], The Art of Cookery Made Plain and Eaſy […] ‎, page 326

The potato, as a mountain tropical plant, is capable of growing in cooler weather than any other tropical except the Nasturtian.

1856, The Horticulturist and Journal of Rural Art and Rural Taste‎, volume 12, page 275

The flowers glowed red and golden: snapdragons and sunflowers, and nasturtians trailing all over the turf walls and peeping in at the round windows.

1954 July 29, J.R.R. Tolkien, “I: A Long-Expected Party”, in The Fellowship of the Ring (The Lord of the Rings; 1)