Webster's Revised Unabridged Dictionary · 1913

Cassidony

Cassidony , noun

[Compare Late Latin cassidonium, French cassidoine. See Chalcedony.]

(a)
(Botany) The French lavender (Lavandula Stochas)
(b)
(Botany) The goldilocks (Chrysocoma Linosyris) and perhaps other plants related to the genus Gnaphalium or cudweed.