||Me*sem`bry*an"the*mum (?), n. [NL.,
fr. Gr. meshmbri`a midday + 'a`nqos flower.]
(Bot.) A genus of herbaceous or suffruticose plants,
chiefly natives of South Africa. The leaves are opposite, thick, and
f?eshy. The flowers usually open about midday, whence the
name.