n.
[植]岩蔷薇

Frostweed \Frost"weed`\, n. (Bot.)
An American species of rockrose ({Helianthemum Canadense}),
sometimes used in medicine as an astringent or aromatic
tonic.

Note: It has large yellow flowers which are often sterile,
and later it has abundant but inconspicuous flowers
which bear seed. It is so called because, late in
autumn, crystals of ice shoot from the cracked bark at
the root; -- called also frostwort.