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Olea
europaea L.
Standardized Common
Name: Olive
Family: Oleaceae
Taxonomy: Olea includes
about 30 species native to warm climates in the Old World. Olea europaea,
the only species that occurs in Europe, is the most widely distributed and the
most variable, with six subspecies recognized in the latest treatment. Its
taxonomy is complicated; O. europaea subsp. europaea alone has
dozens of species-level synonyms, plus subspecific and varietal names. Within
subsp. europaea, which produces the largest and oiliest fruits, O.
europaea var. europaea refers to cultivated olives and var. sylvestris
to their closest wild or feral relatives, which are often naturalized following
escape from cultivation. O. europaea subsp. cuspidata is
widespread in Africa and Southwest Asia; the four remaining subspecies are of
limited range and little economic value.
Description: Evergreen shrub or
tree to 15 m tall. Trunk short, to 1 m thick, the surface conspicuously
irregular with large ridges and pits; crown spreading, rounded; bark silvery
gray; twigs often 4-angled, silvery, covered with scales. Leaves opposite,
subsessile, narrowly elliptic to elliptic, (1–)3–9 cm long, leathery, with
dense covering of peltate scales; base cuneate; apex apiculate to mucronulate;
margins entire, often slightly revolute. Inflorescences axillary, racemose.
Flowers small; calyx fused below, with 4 triangular lobes; corolla yellowish
white, with short tube below, 4-lobed, with lobes reflexed at flowering;
stamens 2. Fruit a drupe, oval, 2–4 cm long in cultivated plants, usually <1
cm in wild plants; unripe fruits green, ripe fruits usually black; mesocarp
fleshy, oily; endocarp large, stony.
Parts
in Commerce:
Leaves
Identification: The key feature of
olive leaf is the presence of peltate scales (with a short narrow stalk and a
broad flat top, rather like an umbrella), which are so numerous on the
underside that they may overlap. The leaf scales of other species of olive are
fewer and often sunken, and few other plants possess similar scales. (The
presence of numerous peltate scales therefore is used for microscopic
identification of powdered olive leaf.) These scales are easily knocked off by
handling, so perfect coats of scales should not be expected in material that
has been harvested and packaged.
- Narrowly
elliptic to elliptic
- (1–)3–8(–9) cm
long, 0.5–2(–3) cm broad
- Margins entire,
slightly revolute
- Apex apiculate
to mucronulate
- Base cuneate;
petiole absent or very short
- Texture thick,
leathery
- Lower surface
silvery (or reddish in some Asian material of subsp. cuspidata),
densely covered with a layer of peltate scales, but without filamentous hairs
- Upper surface
grayish-green to dark green
- Taste bitter
References:
do Amaral Franco J, da Rocha Afonso ML. Olea.
In: Tutin TG, Heywood VH, Burges NA,
et al., eds. Flora Europaea. Vol. 3. Cambridge: Cambridge University
Press; 1972:55.
Green PS. A revision of Olea L. (Oleaceae).
Kew Bull. 2002;57:91–140.
Green PS, Wickens GE. The Olea europaea
complex. In: Tan K, ed. The Davis & Hedge Festschrift. Edinburgh:
Edinburgh University Press; 1989:287–299.
Rushforth K. Collins Guide to the Trees of Britain
and Europe. London: HarperCollins; 1999.
Figure 49: a–b, Olea europaea leaf and close-up of
underside at margin.
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