Nerium oleander L. - Árboles y Arbustos

Nerium oleander L.
Nerium: Ancient Greek name for oleander
oleander: similar to the olive tree (Ital.)
Family: Apocynaceae
Common name: oleander, rose bay
DESCRIPTION
Habit: evergreen shrub 2-4 m tall, densely branched from its base.
Leaves: opposite or in whorls of 3, persistent, simple, with short petioles; blade 15-30 cm long x 2-4 cm wide,
elliptic or lanceolate, with an acute apex, a cuneate base and entire margins, somewhat stiff and leathery.
Flowers: hermaphrodite, apparently subactinomorphic (or almost symmetrical due to the curvature of the
petals), 3-5 cm in diam., in different colours, sometimes double, hypogynous, arranged in terminal corymbiform
cymes; calyx gamosepalous; corolla gamopetalous, formed by 5 white, yellowish, pink or purple petals fused
into an infundibular tube with a crown of elongate dentate appendices at its opening and prolonged into 5
perpendicular lobes arranged radially, 5 stamens with the base of their filaments fused to the internal side of the
corolla tube; gynoecium apocarpous, 2-carpellate, with pistils and a superior ovary.
Fruit: erect double follicle formed by 2 fruitlets (follicles) 8-16 cm long that open releasing numerous seeds with
abundant apical hairs.
FENOLOGY
It flowers throughout the summer; fruits mature in winter.
GEOGRAPHICAL ORIGIN
Native to the Mediterranean region.
OBSERVATIONS
It is often cultivated as an ornamental because of its evergreen foliage, its showy flowers in summer and its
drought hardiness, although it is a very toxic plant due to the cardiotonic glycosides (oleandrine) it contains.
The individuals next to the staircase that communicates the parking lots of both schools are seriously affected by
Pseudomonas syringae subsp. savastanoi, a bacterium that causes tumours on twigs and leaves as well as
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flower abortion (see Picture Gallery). This bacterium causes olive knot in olive trees.
It is easily propagated from greenwood or semi-hardwood cuttings or seeds.
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IMAGES
Branch with leaves in whorls of 3; the midrib is very prominent
Branch with showy flowers arranged in corymbiform cymes; at the centre of each flower, the deeply-lobed corolla has a fringe around the central corolla
tube
Open double follicle releasing numerous seeds with abundant apical hairs
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Branch (adaxial side) and leaf (abaxial side) with tumours caused by Pseudomonas syringae subsp. savastanoi
Inflorescences with aborted flowers caused by the attack of Pseudomonas syringae subsp. savastanoi
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