Agriculture Reference
In-Depth Information
Apples and pears and
their relatives
Taxonomy
Apples and pears belong to the
Rosaceae,
subfamily
Pomoideae
, the pome fruits.
Other members of this subfamily include quince and medlar. The flowers of
the
Rosaceae
are actinomorphic with
petals, numerous stamens and
either one compound pistil or many simple pistils. The number of styles equals
the number of carpels. The
Pomoideae
have mixed flower buds containing both
leaf and flower initials, an epigynous ovary and
sepals,
-
carpels. The
Pomoideae
have a basic chromosome number of
compared with
-
for the other
subfamilies of
Rosaceae
.
The
Malus
(apple) inflorescence is determinate but the descriptive terminol-
ogy is disputed (Pratt,
). It is variously described as a corymb, a corymbose
raceme, a cyme and a false cyme.
Pyrus
(pear) inflorescences have been de-
scribed as umbel-like simple corymbs (Clapham, Tutin and Warburg,
)
and as racemes (Bell
et al.
).
Cydonia
(quince) flowers are solitary.
The typical apple flower (see also Chapter
) has
petals, varying from
white to deep pink,
) with
yellow anthers, and a pistil which divides into five styles united at the base.
The ovary has
sepals,
stamens in three whorls (
+
+
locules, each usually containing
ovules giving a maximum
seed content of
although some cultivars may have up to
( Janick
et al.,
).
P. communis
flowers typically have
, usually white, petals,
sepals and
carpels are completely
united with each other and with the receptacle and there are
-
stamens with red or purple anthers. The
-
ovules per
locule giving a maximum seed number of
styles are free although
closely constricted at the base.
Cydonia
flowers have styles united at the base,
.The
-
carpels and numerous ovules per locule.
The fruits of
Pomoideae
are pomes, commonly described as having a core
with fleshy pith within it and a cortexof flesh outside the core line. There
are two hypotheses as to the nature of these tissues, the receptacular and the
appendicular (Pratt,
).
