CLASS XV. TETRADYNAMIA. 
SILICULOSA. 
183. SEA KALE (Crambe maritima) is a well-known 
plant in our kitchen-gardens, the early shoots of which are 
blanched, and eaten in the same manner as asparagus. 
This plant grows wild on sandy sea-coasts in various 
parts of England; and has been transplanted thence 
into the gardens. The mode of management is, in the 
Autumn, to place large inverted garden-pots over the 
plants, and to cover the whole bed and the pots with 
dung and litter. The heat of the fermenting dung 
causes the plants to shoot early in the spring ; and the 
pots protect them and keep them clear of the litter. 
By this means also, as they have no access to the light, 
they become blanched, tender, and of extremely sweet 
and delicate flavour. 
Sea kale is ready for use some time before asparagus 
appears ; and, for the table, it is preferred by most per- 
sons to that favourite vegetable. If the leaves of sea 
kale be eaten when full grown, they are said to occa- 
sion giddiness ; but horses, cows, swine, and other ani- 
mals, feed upon them without injury. 
184. WO AD is a dyeing drug, produced by a British plant 
(Isatis tinctoria), with arrow-shaped leaves on the stem, yellow 
cruciform flowers, and oblong seed-vessels, each containing one 
seed. 
This plant is believed to have been the same that 
was adopted by the ancient Britons for staining, or 
painting their bodies a blue colour, to render them, in 
appearance, at least, more terrible to their enemies. It 
grows wild on the borders of corn-fields, in some parts 
of Cambridgeshire, Somersetshire, and Durham: and 
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