Webster's Revised Unabridged Dictionary · 1913

Mesembryanthemum

Mesembryanthemum , noun

[New Latin, from Greek meshmbri`a midday + 'a`nqos flower.]

(Botany) A genus of herbaceous or suffruticose plants, chiefly natives of South Africa. The leaves are opposite, thick, and fleshy. The flowers usually open about midday, whence the name.