One useful feature that is not immediately available in the field
is the seeds. Until the vascular connections between the individual
fruits held in the crown and the parent tree are broken, the valves
will not open. Otherwise, eucalypt fruit are held on the branchlets
often for years. Seed from detached fruits, however, can be ready
for inspection after about 24 hours by placing unopened fruits in
a paper bag where they dry out quickly and shed the
seeds and the thinner chaff particles. There is a great number
of seed forms and these can be seen either with the naked eye or
by means of a lens. Fortunately, related species have identical
seeds and the character is therefore one of high reliability. Because
words do not adequately convey the actual seed shape for most species,
experience is needed to educate the user who will ultimately find
the seeds to be an invaluable aid in discriminating species and
groups of related species. We suggest the following terms as a guide.
Flattened or saucer-shaped
The seed is somewhat flattened with a distinct upper (dorsal)
and lower (ventral) side. The ventral side may be somewhat
concave, with the hilum in the centre. Angophora
and the ghost gums have this type of seed.
Pyramidal or obliquely pyramidal
The seed is pyramid shaped with a relatively smooth or lacunose,
flat or rounded dorsal side. The ventral side is usually ribbed,
wrinkled or angled and is surmounted by a narrowed face at
the summit where the hilum is
(e.g. E. acmenoides).
This is the seed type in most of the monocalypts although
there is a great amount of variety in their seed form. Perhaps
the most extreme seed shape in the monocalypts is seen in
some western endemics, e.g. E. buprestium and E.
todtiana, in which the body of the seed is small in
comparison to the grossly extended curved lateral wings.
The seed is elongated and strongly keeled dorsally with a
large, conspicuous hilum in the middle of the flat underside.
The edges may be flanged or narrowly winged. E. gummifera
and E. calophylla
notably have this type of seed.
The seed is chunky, often with a smooth, shiny or somewhat
granular, sometimes slightly rounded, dorsal side. The hilum
is situated on a smaller terminal face separated from the
dorsal side by the side walls of the seed. These walls are
often angular. The chaff is usually similar to the seed, but
somewhat smaller and lighter coloured (e.g.
Ellipsoidal with terminal wing
The flattened-ellipsoidal body of the seed occurs at the lower
end (considering the disposition of the ovule on the placenta
in the intact bud), with a transparent wing as long as the
body of the seed at the top end. Overall colour of the seed
is reddish or yellowish brown. The wings may be seen, just
before seed shed, emerging from the top of the ovary. The
hilum is usually positioned near one edge not far from the
start of the wing. The wing is purely a descriptive morphological
term and the structure has no apparent aerial function. Most
of the bloodwoods have this type of seed
(e.g. E. chippendalei).
Pointed at one end
The seed is somewhat flattened, usually rounded at one end
and pointed at the other. It may be described as teardrop-shaped
The seed is roughly disc-like with a short straight side and
a longer connecting curved side. The hilum is towards the
narrowed end (e.g. E.
The seed is more or less spherical (e.g. E.
Ovoid or depressed ovoid
The seed is ovoid or elliptical in outline but flattened with
the hilum on the more or less concave ventral side (e.g.
A large number of species have this type of seed which are
otherwise difficult to describe. Examples are the section
Maidenaria, endemic to eastern Australia, in which the dorsal
surface is often lacunose, and a large number of mallees occurring
across southern Australia. These seeds have very smooth dorsal
sides with two or three shallow longitudinal grooves. This
is seen particularly in series Subulatae and Calycogonae.
Obliquely elongated: the
seed is like a narrowly drawn-out pyramid with the dorsal
face curved and prolonged into a thin "tongue".
The terminal face is small, flat and oblique on the seed with
the hilum in the middle. The sides are ridged (e.g. E.
The seed is narrow and elongated, with a very small dorsal surface,
long sides and terminal hilum (only E.