Thorns, Prickles, Spines and
Bristles
Plants have several
ways to grow armor to discourage animals from browsing on them.
A thorn is a sharp,
pointed, modified branch or stem. It can
be at the end of a stem, or be its own short pointed woody branchlet.
Buffalo Berry – photo courtesy Steve Matson
A prickle is an
outgrowth from the skin of the stem.
It’s a kind of stiff, sharp hair that grows from the epidermis.
Himalayan Blackberry – photo courtesy Zoya Akulova-Barlow
A spine is a hard,
sharp, pulled-together leaf or flower part.
They’re often found at leaf margins.
Sometimes the whole leaf becomes a spine, such as with Cactus.
Arizona Thistle – photo © Frank Rose, Desert Museum
A bristle is a dry,
colorless, stiff hair. In leaves,
bristles are an extension of a leaf vein that goes beyond the margin.
Black Oak – illustration © John Muir Laws
In dandelion pappus,
bristles are appendages to the fruit, creating a parachute to fly away on.
In fact, the term
bristles, as with hairs, is more about the look of an appendage rather than its
structure. Stems and flower parts have a
wide variety of them.
Want more? See Wikipedia.
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