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Glandulicactus wrightii
Areole and spine cluster on an isolated tubercle
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Spine clusters are typical
structures characteristic
of the Cactaceae
family, they develop from a
meristematic growth centre
called the areole which is
positioned on the tubercles
(raised , domelike or elongate areas along the
stem) or on the
ribs.
Each spine cluster (corresponding to an
areole) may contains
central and
radial spines and
also glochids,
hairs,
leafs or
glands. |
