description
Silybum marianum is an annual or biannual plant of the Asteraceae family.
This plant can take on impressive proportions: it grows from 1 to 6 1/2 feet
in height with its base at times reaching nearly 5 feet in diameter. Milk
thistle grows in a conical shape, the stem being grooved and somewhat
cottony. In the
larger specimens the stem is hollow.
Milk thistle's leaves are oblong to lanceolate— and they are either lobate or pinnate, with
spiny edges. The leaves also have milk-white veins, are devoid of hair, and are shiny green.
The red-purple flower
heads are 1 1/2 to 4 3/4 inches long and wide. They flower in the summer through autumn (more specifically from June
to August in the North and from December to February in the Southern Hemisphere). Like its leaves, milk thistle's bracts are hairless,
but have triangular, spine-edged
appendages, that are tipped with a stout yellow spine.
The achenes (small, dry, one-seeded fruits) are black, with a simple long white pappus, surrounded by a yellow
basal ring.
common names & nomenclature
Legend states that the milk-white veins of the leaves originated in the milk
of the Virgin which once fell upon a plant of Thistle, hence it was called
Our Lady's Thistle; the Latin name of the species has the same derivation.
Also known as:
Cardus marianus, milk thistle, blessed milk thistle, Marian Thistle, Mary Thistle, Saint Mary's Thistle, Mediterranean milk thistle,variegated thistle, Scotch thistle.
Not to be confused with Centaurea benedicta
(aka Cnicus benedictus, aka Blessed Thistle).
