It is an error to pronounce the name of the shrub ceanothus as '
sigh-an-OATH-us' (IPA: / ,saɪ ə 'nəʊ θəs/. It is pronounced 'see-an-OATH-us' (/,siː ə 'nəʊ θəs/).
The name of the shrub, of which different species have flowers ranging in colour from white through brilliant blue to pink, is derived from the same root as cyan and various combining forms such as cyano- . This yields the names of many chemicals and minerals, such as cyanochalcite. Ceanothus, best known to gardeners as a shrub or small tree with brilliant blue flowers (ceanothus Americanus), is derived rather more distantly from the various scientific meanings: the origin of both is Greek κύανος (kuanos), the name of a dark blue mineral. The various chemical names reflect this colour; in biomedical sciences, cyanosis is the abnormal blueness of skin caused by lack of oxygen in the blood, by such causes as the poison cyanide, one of a number of poisons formed by compounding cyanogen, a radical, with a metal, or an organic chemical. Potassium cyanide and prussic acid are two notorious poisons of this type - at least in detective stories.
- But the garden plant is written - and pronounced - with '-e-' as its first vowel.