BLUMEA
36
501-514
(1992)
comparison of the structure
A
of ovules
and seeds in
Stemona (Stemonaceae) and Pentastemona
(Pentastemonaceae)
F.
Hugo de
Vries
Bouman
&
N.
Laboratory, University
Devente
of
Amsterdam,
Kruislaan
318,
The Netherlands
1098 SM Amsterdam,
Summary
Stemona
the
cially
the
origin
acters
and Pentastemona differ
of the seed
support
the
ridges,
proposal
clearly
and cell wall
development, shape,
show marked
to
give
in
the size and structure of their ovules and seeds.
of the endotestal
thickenings
differences. The embryological
Pentastemona a
family
and
cells,
Espe-
by consequence
and seed anatomical char-
status.
Introduction
The
of the small
embryology
monocotyledonous family
iaceae)
has been reviewed
(1990);
the seed anatomy of the
known from the detailed
characterized
Stemona is
by
Davis
(1966)
study by Swamy (1964)
with
layer.
The
Tomlinson &
Ayensu (1968)
anatropous
and
bitegmic.
Rogers (1982)
Huber
family
is
(1969)
al.
et
mainly
known.
the ovule of Croomia
a
of
other genera of the
two
insufficiently
gave
coat
originate by local, periclinal
of the
embryology
viz. Croomia and Stichoneuron, is
also
The
of Stemona tuberosa. Stemona is
which
Stemonaceae,
and
(Roxburgh-
and crassinucellate ovules. The seed
longitudinal ridges,
divisions of the endotestal
Stemonaceae
recently by Batygina
more
family by Takthajan (1985).
by anatropous, bitegmic
provided
and
description
According
pauciflora
of the seed
coat
to
is
of
Croomia.
The
newly
described genus Pentastmona Steen.
in the Stemonaceae because
similar seed
mona
as
vesicular
structure
anatropous,
body.
(1985). They
and
a
with
The familial
i.a. all four genera
was
placed by
said
were
Van Steenis
share
to
a
(1982)
surprisingly
characteristic aril. He described the ovules of Pentastetwo
integuments,
status
found the genus
and
the aril
of Pentastemona was
highly distinctive,
as
an
lobed
irregularly
questioned by Dahlgren
about as distinct
as
Trichopus
et
al.
or even
Tacca.
In this paper the
more
to
detail and
the
Ham
recent
(1991)
flower
structure
compared
of the ovule and seed of Pentastemona is described in
with that in Stemona. The
contributions of Duyfjes (1991)
on
the
morphology
pollen morphology,
on
the
current
study is complementary
general morphology, of Van der
and of Van Heel
(1992, present issue)
of the Pentastemonaceae and Stemonaceae.
on
the
BLUMEA
502
VOL.
MATERIALS
Most material
van
AND
the
supplied through
was
No.
36,
1992
2,
METHODS
of B.E.E.
generosity
and W. A.
Duyfjes
Botanicus, Leiden. The following material has
Heel, Rijksherbarium/Hortus
been studied:
Miq.:
Croomia japonica
P.
Hatusima 19946
sumatrana
(L).
Steen.:
Bogner 1724,
cult. Bot. Garden L and M.
Steen.: de Wilde & de
Wilde-Duyfjes
20311
egregia (Schott)
Pentastemona
Stemona australiana
C.H.
(Benth.)
2333
(L).
natensis
S.
-
prostrata
Stichoneuron caudatum Ridley:
The material was
methacrylate,
submitted
nium
to
red, nigrosine,
were
stages
was
in
a
were
in
an
out
were
21411
japonica
var.
or
by
ter-
(L).
cult. Bot. Garden M.
stained
glycol-
by periodic acid/
microtome sections
phloroglucinol/HCl,
aniline
were
ruthe-
sulphate,
and Sudan IV.
of
means
gold-palladium
ethyl
S.
-
S. tuberosa Lour.
-
(L); Bogner 1789,
potassium iodine,
carried
with
sputter-coated
dehydrated
(L).
Wilde-Duyfjes
toluidine counter-stain. Hand-cut
iodine in
(DNA).
normal butyl alcohol series, embedded in
tests:
—
21399 (L).
javanica (Kunth) Engler, Beguin
5 pm. The sections
at
several histochemical
The SEM studies
seeds
a
de Wilde & de
Corner 30503
dehydrated
and sectioned
Schiff's reaction with
S.
Telford: Craven 5546
(J.J. Smith) Duyfjes:
1063
Wright: Wightman
Franch. & Sav.: Hortus Pekinensis 82.631.
(L),
for
an
c.
ISI-DS
130
9 kV. Mature
at
3 minutes. Material of younger
alcohol series and critical
point-dried
with
CO2.
RESULTS
Ovule
in
structure
The ovules
Ovules in
are
cross
Pentastemona
egregia
bitegmic, anatropous,
section almost round, with
fertilization the ovules
have
already
(Figs. 1, 4—7)
crassinucellate and
some
a
measure c.
410
raphide
x
264 pm.
At the time of
slightly protruding raphe.
idioblasts in the tissues of raphe and
chalaza. In the funicle and raphe intercellular spaces develop between the epidermis
and the
subepidermal
and
xylem
chalaza. The ovules
The
outer
12 to 17 (mean
about 45
are
are
through
passes
embedded in
integument
those sites there
single, small, amphicribral
cells. A
elements
phloem
is about 35
a
to
slightly staining
40 pm
thick,
small intercellular spaces. In
15) tangentially
bundle with
the funicle and
2, locally 3, layers
section the inner
stretched cells. These cells
are
25
integument
is 20
to
25 pm thick, and consists of
the
to
60
thick. At
layer
pm
counts
wide (mean
2, locally 3, layers,
without intercellular spaces. The cells of both the inner and the
or
at
pm).
The inner
more
differentiating
and ends
'mucous' substance.
and
cross
raphe
outer
layer
are
but
small,
less isodiametric.
The micropyle is formed by the inner integument only. The endostome opening is
in direct
contact
with
cells of the inner
divide
swollen, pollen-conducting
layer
periclinally.
of both the endo- and
The aril is initiated
tion of intercellular
spaces and
by
at
cells of the
exostome
parietal placenta.
elongate radially
about the time of fertilization
divisions of the dermal cells
funicle and raphe and of the neighbouring exostomal rim.
at
by
the
The
and may
the forma-
junction
of
F. Bouman
The
embryo
mature
length of
& N. Devente:
the nucellus and is
The nucellar
part.
stretched
slightly
part of the embryo
sac
surrounded
by
basis of the
embryo
a
hypostase-like
a
way
megaspore
Seed
structure
The seeds
x
840
pm),
in
provided
micropyle
more
pronounced
Raphe
is
'cortical'
chalaza.
to
seed. The aril is
intercellular
about 130
about 180 pm
space.
The
cross
of
a
micropyle
plane,
eral
up
to
long
and surrounded by
and chalaza have
cells have
once,
with
outer
cells
corresponds
remain small and do
and is
with the
ridges
not
of the
wall is
small in
third of the
one
a
single large
cell walls and
outer
is
to
not
increased
230 pm
the
(mean
one
so
195
integument
arranged
rows
pit
has
sev-
canals. The endotesta
have stretched
places
thin. The
starch
radially
As
considerably.
a
about 15 pm
is
for the
exotesta
grains.
the cells of the
layer
Except
of about 60 cells. As
longitudinal sections (mean height
near
120 pm
and
The radial walls of the endotestal
endotestal cell.
some
pm)
to
of
peri-
outer
evenly thickened,
that the exotestal
exotesta are
seed
during
thickening
less reticulate and
tapers
more or
narrow
into
developed
surface of the seeds. As
U-shaped by
of the seed. At these
and the cells contain
in
vas-
raphide
stains. At the incurvature of the endotes-
outer
the number of the endotestal cells has increased
pyle they
about
integument
outer
more
with
periclinally.
divide,
wall, the cell walls of the
are
some
the incurvation of the thin
by
provided
lignin-specific
layer
cells thick and about 9 cells span
tanniniferous,
insignificant
with
locally
covers
outer
ridged
of the radial walls is
sometimes twice
layer
outer
SEM. The
copious endosperm.
an
thickened
slightly
from 140
length
The inner periclinal
distinctly
look
ridges
by
centred around the nucleus.
the endotestal cells appear
thickening
tal cells the cells of the
may divide
the
270 pm. The inner periclinal cell walls vary from 90
periphery.
not react
and
vesicular collar and
a
which determines the
differently staining layers,
does
exotesta
than when viewed
section, the number of endotestal cells has
In this
100 pm). The
towards the
longitudinal ridges running
one-layered epidermis enveloping only
epidermal
layer,
900 pm in width (mean 1070
to
faint
peripheral parenchyma
clinal walls. The radial walls vary in
(mean
(figs. 2, 3, 8, 9).
structure
raphe
the radial and inner periclinal cell walls and
the
12)
endotestal. The inner layer of the
are
development.
elongate radially
65 pm.
x
composed
very characteristic
counted in
The
(Figs. 10—16)
microscope
large compound amyloplasts mainly
The seeds
a
and is
thickenings.
axial strand of nucellar
an
the transparency of the
to
under the binocular
The aril has the appearance of
contain
long
visible from the outside. The
measuring
The chalazal
monocots
many
cells. These cells
and 750
13 (mean
to
Owing
cular bundle almost without
cells
by
half the
its upper
at
cells become
apical
distinct cell wall
similar in
are
sumatrana
1150 pm
to
with 10
relatively small,
not
Its
periclinally.
for
characteristic
over
epidermis
periclinally.
times
Pentastemona
about 950
from
embryo
divide
not
503
Pentastemona
tetrad is linear.
are
and
the nucellar
by
showing
structure
by radiating
or more
and
Polygonum type, occupies
but do
The ovules of Pentastemona sumatrana
The
Stemona
is connected with the chalaza
which is surrounded
cells,
and may divide one
in
in
entirely one-layered.
papillate,
narrows
sac
of the
remains
and
seeds
covered
mainly
epidermis
radially
and
probably
is
sac
Ovules
is
only
one
slightly
to
outer
three
thickened
fully transparent,
seen
in
not
length sections,
From chalaza to micro-
result the cells appear very
only).
BLUMEA
504
seed
During
Its
those of the inner
until
geneous cell wall
early stage
testa
has
In the
they collapse.
tinct cellular organization
very
the inner
development,
cells, especially
stretching,
along
nucellus is present,
as
outermost
After
fertilization,
embryo
mic wall ends
a
the endo-
wall of the inner in-
thin dark-staining layer of compressed
wall
a
layer
between
endotegmen
and
Near the chalaza the
origin.
structure
the
outer
has overgrown the inner one, and closes
integument
mature
seed the endostome forms
small
a
above the
plug
of tanniniferous cells with somewhat thickened walls. The teg-
abruptly
at
the
plug.
endosperm fills the major part of the seed. The cells vary in size,
The
dis-
layer.
the endostome. In the
and consists
a
homo-
a
is present in
layer
thickening of
tanniniferous tegmen and nucellus may have retained their cellular
slightly
and their interfacial wall
over
This
tests.
endotegmic
of
shows
longer
no
mainly present
the cell wall
from the
a
Locally
present.
probably mainly
enlargement mainly by
seed, the tegmen
with cutine
wall
increase in thickness.
not
of its surface but is
tegmic layer originates
and nucellar cells is
tegmic
does
follow the seed
already before
tegument. Underneath the exotegmic
1992
2,
integument
layer,
layer, slightly reacting
The
No.
36,
mature
most
after fertilization,
begun.
VOL.
thin-
are
walled, and contain various storage materials; starch grains mainly around the embryo
and
near
the
chalaza,
uted. There is
cells
peripheral
in
tively
as
layer.
well
as
lipids being
The cells
measure
there is
small
a
in Stemona tuberosa
zone
var.
bitegmic, anatropous
are
about 600
x
of
ternatensis
and
distrib-
only quantita-
200 pm. Funicle and
raphe
without
distinct bundle sheath, but surrounded
a
The chalaza becomes
ring-
and
spiral-xylem
of the vascular bundle.
periphery
have
contain
elements and
quite prominent by periclinal
Raphal
a
a
distinct
raphe,
relatively large
am-
differentiatedphloem,
a
several
by
tissue.
(Figs. 17—20)
crassinucellate,
bundle with
the
generally
the suspensor and the
disintegrating endosperm
phicribral
at
more
surrounding
somewhat smaller than the central ones, but differ
embryo
structure
The ovules
and
are
grains
outer
contents.
Around the
Ovule
aleuron
distinct
no
layers of parenchyma.
divisions of the
and chalazal
parenchyma
parenchyma
cells
without
distinct intercellular
spaces.
Outer and inner
ness,
The
exostome
does
is in direct
contact
velopment
starts
and
proceeds
to
integument 2-, locally 3-layered, about 20
Cells of all
respectively.
not
with the
with
the
layers
protrude
more
or
adjacent
or
and
15 pm in thick-
somewhat
elongated.
above the endostome. The endostomal
pollen-conducting
periclinal,
less cubical
tissue of the
placenta/funicle.
later anticlinal divisions of dermal cells
exostome
rim. Aril
initially
at
opening
Aril de-
the funicle
without distinct intercellular
spaces.
Nucellus
large, composed
of many small cells and without the radial cellular
rangement as in Pentastemona.Nucellar epidermis one-layered, the cells
stretching radially
probably of
the
and sometimes
dividing periclinally. Embryo
Polygonum type, occupying
about
1/3
to
sac
chalaza and inner
layer
of outer
integument
its
ar-
apex
pear-shaped,
1/4 of the length of the
nucellus.
Raphe,
at
with starch
grains.
F. Bouman
Seed
Ovules
N. Devente:
and
in Stemona australiana
structure
The seeds,
&
excluding
aril,
the
less
raphide
small,
pronounced
cells. The
at
the
Stemona
and
mm
varies within the
18 in
australiana, and
about 1.3
raphe. Embryo
mm
seed. Aril
of many,
composed
Pentastemona
505
with distinct
provided
species;
S.japonica.
Seed
long.
number
mean
The
ridges
without
coat
overgrows the endostome after fertilization. Endostome
exostome
tanniniferous and without thickened walls, still
not
and
(Figs. 21—39)
ridges
about 27 in Stemona tuberosa, 24 in S.
are
in
about 7x4x4
are
The number of
longitudinal ridges.
seeds
the funicle
at
in the
recognizable
superimposed,
flat
locally
or
mature
hollow
hairs. Outer periclinal cell walls thickened, cells with very few small starch grains.
The seeds
endotestal. The
are
and
multiplicative
the grooves. In
endotestal cells
crete
radial
Two innermost
Endotestal
the exotestal
layered
at
cross
rows
layers
of the endotesta
Cells of the
the top of the
ridges,
develop.
walls of the
exotesta
development
same
Tegmen
as
by
between the
about 3
to
opposite
an
and
exo-
Cells of the
outer
seed. Inner
mature
ognizable,
of
layer
resorbed, except for
some remnants
Endosperm initially nuclear,
ed,
more or
the central
of various
periclinal
near
one-
at
the
at
the top of the
the cells
adjacent parts
raphe
at
the flanks
of the radial
and chalaza show the
testa.
layer
of the
tegmen somewhat
and with thickened inner
testa.
division pattern of
dividing periclinally
cell walls and the
of the
part
of the
less cubical and
or
width,
with
periclinal wall, stretched tangentially and longitudinally
the
layer
and endotestal cells, intercel-
4 times their
peripheral layers
integumentary
4 cells
to
Walls of the
stretched.
more
radially stretching
thickened. The
the
rows.
No distinct inner
tangentially
layer small,
periclinal
multiplicative.
not
but
and 2
ridges
3 cell
Exotesta tanniniferous. Exotestal cells
Outer
ridges polygonal.
outer
ridges,
ridges longitudinally stretched,
of the
more
to
are
several times
less reticulate, and with small less dis-
become somewhat flattened
ridges
layer.
lular spaces may
or
only slightly ligniferous.
At the flanks of the
grooves.
more
the
at
2
by
integument
outer
layer dividing
high
formed
ridge
section each
of the
layer
Inner
of about 10 cells
slightly thickened,
Endotesta
pits.
and inner
develop longitudinal ridges.
periclinally, forming
at
outer
slightly
and
thickened
outer
mostly compressed
tanniniferous, locally
wall. Nucellar tissue
in
still rec-
compressed
or
the chalaza.
later cellular. Cells of the
endosperm radially
arrang-
less isodiametric and thin-walled. Peripheral cells somewhat smaller than
ones.
Outermost cell walls
aleuron
size,
grains
and
slightly
thickened.
lipids. Endosperm
Endosperm
around the
with
amyloplasts
embryo disintegrat-
and without storage material.
ing
The seed
stance, seed
10)
rows
the
outer
Ovule
coat
in S.
japonica
of endotestal cells per
layer
at
structure
The ovules
250 pm.
anatomy of the various Stemona
ridges
as
compared
ridge
species
may
differ in detail: for in-
with S. australiana with
and with less manifest
periclinal
more
(about
divisions of
the furrows.
in Stichoneuron caudatum
are
anatropous, bitegmic and crassinucellate, and
Raphe prominent
with differentiatedxylem and
inner
integument mainly 2-layered.
inner
layer
of the
outer
integument,
Cells
which
more or
are
less
elongated
phloem
measure
about 360
x
elements. Outer and
cubical, except
those of the
in the radial direction.
BLUMEA
506
The
VOL.
cells of the nucellar apex
epidermal
to
the
and in
with the
contact
1992
sac
with
and divide
an
to
far above the rim of the
protruding
pollen-conducting
periclinally
arrangement compar-
multicellulartrichomes of
funicle/placenta.
seed material
Adequately preserved
Seed
less
in Croomia
structure
The
general
about the
The
Each
testa.
ridge
tangentially
of the
seed resembles that of Stemona. The
mature
of
shape
ridge,
a
is
composed
1
only
and
pronounced
of 2
to
4
and has
(mostly 2)
in Stemona. The walls of the exotestal cells
lar spaces
occur
at
flanks of the
the
and endotestal cells
exo-
rows
ridges,
also
divisions of the endo5 cells
to
layer
high.
layer
outer
the grooves
at
as
thickened. Intercellu-
exo-
raphide
Endotesta
of the endotesta
thickened. The
slightly
between the
tanniniferous. No
slightly
of 4
divided periclinally
are
is
longitudinal ridges.
Innermost cell
not
raphe
bundle with differentiated xy-
slightly reticulately
and has
entirely one-layered
a
originate by periclinal
2 cells in thickness.
or
stretched. Endotestal cells
is
testa
less
are
the grooves
available.
elements. The seeds have about 21
phloem
ridges
not
japonica
of the
structure
prominent,
lem and
at
embryo
that in Pentastemona. Endostome elongate,
integument
outer
2,
elongate radially
form a small nucellar cap. Cells below the
able
No.
36,
and endotesta. Both
cells
present in the
are
testa.
better
Tegmen
The
continuous wall
and form
layer.
nucellus
than in Stemona. Two cell
walls of the
somewhat
a
compressed
The
preserved
periclinal
outer
exotegmic
Inner periclinal
recognizable.
a
distinct
thickened likewise
layer. Locally
of the
remnants
present.
consists of
copious endosperm
peripheral
often still
endotegmen
wall
thinner, parallel-running
are
layers
thickened and form
are
walls of the
radially arranged, isodiametric,
cells and is stored with starch and aleuron
in both the
cells
grains
and central cells of the
and
lipids.
The
thin-walled
amyloplasts
occur
endosperm.
DISCUSSION
The
as
similarity of the ovule
posed by
this
Van Steenis
study clearly
velopment and
taxa
(1982)
nounced
bigger
states
in all
a
superficial
true
one.
The data from
appreciably
in the de-
that the ovules of both
structure
are
and hold
angiosperms
true
for the
are
majority
Pentastemona,
especially
caused
by
a more
much
of the ovules
bigger
are
and have
a
also
expressed
in the
mature
well-developed raphe
pro-
appears often
to
Comer's
problematic
terminology,
in the
so
seeds.
and chalaza.
the seeds show marked differences in the anatomy of their seed
dicotyledons,
the
of the
chalaza and the nucellar base.
Characterization of seeds according
the
only
the ovules show several differences in detail. The ovule
than that of
The differences in the
The seeds of Stemona
to
be
and crassinucellate, but these
anatropous, bitegmic,
as
character
development of the
Moreover,
appears
to
of their ovules and seeds. It is
structure
monocotyledons. Besides,
of Stemona is
between Stemona and Pentastemona
structure
show that Stemona and Pentastemona differ
may be described
plesiomorphic
and seed
coats.
successfully applied
monocotyledons because of the
F. Bouman
presence of
wall
tegmic
than
more
one
In
layer
in the seed
layer
with the
provided
found in many taxa,
at
the
with
the
the
disregards
one
ridges,
as
of the endo-
thickenings
quite different.
are
have
longitudinal ridges.
level for instance in
family
507
may be characterized
monocotyledons
number of
a
Pentastemona
If
coat.
species
of the seed
origin
dicotyledons,
and
and cell wall
development, shape
consequence the
by
comparison
with seeds
taxa
mechanical
Stemona
in
of Pentastemona, the seeds of both
endotestal. However, the
testal cells, and
seeds
Ovules and
N. Devente:
&
relatively
many
seeds
Ridged
are
Eriocaulaceae, Pontederiaceae,
Stemonaceae, Taccaceae, Xyridaceae, and Zosteraceae,
at
the genus level in
Anigo-
zanthos, Blancoa, and Conostylis (Haemodoraceae), Cyclanthes and Dicranopygium
Ctenanthe (Marantaceae),
(Cyclanthaceae),
and
(Araceae),
as
well
as
at
the
level in
species
the anatomical structure of the
able differences. Seed ridges
of the
monocotyledons.
pathways. They
may
originated
ontogeny
originate by
the
in the
ridges
have
must
The
and Philodendron
(Bromeliaceae),
Navia
The ontogeny
Aponogeton (Aponogetonaceae).
of the
mature
seeds may show consider-
several times
seed
the evolution
different
ridges proceeds along
of cells of the
shape
during
layer
outer
of the
outer
integument (Burmannia, Thismia), by divisions of the endotesta (Stemona), by the
of the endotestal cells
shape
(Pontederia),
the
by
or
of
shape
cells
exotegmic
(Xyri-
daceae, Tacca). The presence of the U-shaped endotestal cells in Pentastemona and
their expression
in the striate seed is
seed
Probably,
ridges
are
functional in the
dicotyledons, monocotyledons
ious
species.
1920; Cronquist,
of
dispersal
(nautochory)
(Van
der
low
and
or
Pijl, 1982).
hydrochorous
marshes,
a
prefer
swamps,
rainwash
may promote
and
Due
Huber
are
available
on
the type of
and
Dahlgren
et
al.
to
special
water.
an
of
or
of forests
amphib-
on water
frequent
70% of the
devices such
to
as
sur-
may have
the small
size,
floating tissues,
the surface and
This may
at,
occurrence
species
Next
or
(Arber,
role in the
important
drifting
is of
observation).
of
a
especially
capturing
air
be effective in
by
Stichoneuron also) share the
testa
tion of the
in Pentastemonaceae and Stemona-
dispersal
must not
probable.
seems
myrmecochory
for Stemona and
be ruled
out
number of differences in the seed anatomy of Stemona and Croomia
probably
statement
dispersal
(1985) suggested
recorded
Huber
(1969), according
to
our
same
own
observations these
basic seed
coat
genera
structure, viz.,
a
(and
ridged
which originated by periclinal divisions of the endotestal layer. Also the
of Huber (1969) that Stemonaceae are characterizedby
outer
and inner testal
Although
exotestal
cells
somewhat
the apex of the
ridges
are
are
crosswise orienta-
elongated tangentially, only the
layer
longitudinally
is
a
confirmed.
layers ('Kreuzschichtung')
the cells of the inner endotestal
at
generally
However, diplochory, including hydrochory,
spite
(striate)
plays
means
the presence of distinct arils zoochorous
to
(1969)
Croomia.
In
water
with
compared
aquatic
medium-sized seeds.
to
No data
ceae.
of
understorey
floating by enlarging
bubbles between the surfaces of seed and
small
of seeds. As
environments and grow in,
the
temperate wetlands even up
dispersal (Bouman, personal
the seeds
on
wet
in
(ombrochory)
specific weight, repellent surfaces,
ridges
or
hydrochorous dispersal by
by
In
dispersal
relatively high proportion
In these environments
1981).
seeds,
faces
a
have
Many monocotyledons
lakes, pools,
rivers,
the situation in Ponte-
strikingly paralleled by
1985).
deriaceae (Takhtajan,
not
stretched in Stemona.
BLUMEA
508
1992
2,
justified
not
for the
related
possibly
from the so-called
taxa
endotesta, Taccaceae
a
and
structure
para-Dioscoreales
a
lack of
by
compare the ovule and seed
moment to
and Stenomeris. Most members of the Dioscoreaceae have
chopus
structure
such
Tri-
as
cystalliferous
well-developed exotegmen.
In conclusion, the differences in the
and Pentastemona reported here
the
No.
36,
in view of the substantial variation in seed
Regrettably,
detailed data it is
with those of
VOL.
structure
support
implementation by Duyfjes (1991)
the
of ovule and seed between Stemona
of
suggestion
Dahlgren
rank Pentastemona as
to
a
et
al.
and
(1985)
separate family.
ACKNOWLEDGEMENTS
The
viding
Prof.
were
authors wish
material
and
to thank
for
A.D.J. Meeuse
kindly put
Brigitta
for correcting
the
Wim
disposal by
at our
Duyfjes
E.E.
and Willem
A. van Heel
Dieter Boesewinkel
stimulating discussions,
manuscript.
The SEM
for their
for technical
help
in
proand
assistance,
photographs 8, 9, 11,15, 16,
and
32
Heel.
van
REFERENCES
A.
ARBER,
Waterplants. University Press, Cambridge.
1920.
BATYGINA, T.B.,
(eds.). 1990. Comparative embryology
al.
et
dones, Butomaceae-Lemnaceae.
E.J.H.
CORNER,
CRONQUIST,
Press,
1976. The seeds of
A.
New
1981.
Press,
DAVIS,
G.L.
DUYFJES,
&
H.T. CLIFFORD.
H.T.
evolution
1966.
CLIFFORD
and taxonomy.
of classification
The
1982.
of
Colombia
flowering plants.
monocotyledons;
& P.F. YEO.
VAN DER.
HAM, R.W.J.M.
of the
Systematic embryology
Blumea
1992.
W.A. VAN.
36;
Univ.
a
comparative study.
Aca-
The
families
of the
monocotyledons.
Berlin.
angiosperms. Wiley,
Pentastemonaceae; with
New York.
miscellaneous
notes
on
members
239-252.
1991.
Floral
1985.
Springer Verlag,
B.E.E. 1991. Stemonaceae and
of both families.
HEEL,
dicotyledons. University Press, Cambridge.
integrated system
London.
DAHLGREN, R.M.T.,
Structure,
flowering plants. Monocotyle-
York.
DAHLGREN, R.M.T.,
demic
An
of
Nauka, Leningrad. (In Russian.)
Pollen
morphology
of the
Blumea
Stemonaceae.
morphology of Stemonaceae
36:
and Pentastemonaceae.
127-159.
Blumea
36:
481-499 (this issue).
HUBER,
H.
1969.
Die
Samenmerkmale
Staatssamml. Munchen
PUL,
L. VAN DER.
ROGERS,
G.K.
8:
of
1982. Principles
1982.
und
Verwandtschaftsverhaltnisse der
Liliifloren.
Mitt. Bot.
219-538.
dispersal
The Stemonaceae in
in
higher plants.
Ed. 2.
the southeastern United
Springer Verlag, Heidelberg.
States. J. Arnold
Arbor. 63:
327-
336.
STEENIS,
C.G.G.J, VAN.
North Sumatra
SWAMY, B.G.L.
osa Lour.
TAKHTAJAN,
1982. Pentastemona,
(Stemonaceae).
1964. Observations
Phytomorphology
A.
Blumea
(ed.).
14:
on
28:
the
a
new
5-merous
genus
of
Monocotyledons
from
151-163.
floral morphology
and
embryology
of Stemona tuber-
458-468.
1985. Anatomia
seminum
comparativa.
1.
Lilicpsida
seu
Monocotyledones.
Nauka, Leningrad. (In Russian.)
TOMLINSON, P.B.,
monaceae).
&
E.S.
J. Arnold
AYENSU.
Arbor. 49:
1968. Morphology
260-275.
and
anatomy
of Croomia
pauciflora (Ste-
& N. Devente:
F. Bouman
Ovules
EXPLANATION
Plate
1.
x
2 &
3: P.
145 and
ovules
median
sumatrana,
90
x
respectively.
level
at the
OF
(LM).
1-7. Pentastemona ovules
-
of the
and
THE
1: P.
-
P.
in
Stemona
PLATES
Pentastemona
and
longitudinal section,
detail
of aril
cross section of ovary
egregia,
and
509
(Figures 1—39)
section
funicle, micropyle
and
transmedian
egregia,
longitudinal
4-7:
-
seeds
embryo
x
45,
(LM
and
sac,
of
and cross
350,
x
170.
x
developing seed,
sections
245,
x
of
160
x
respectively.
Plate
2.
8-16. Pentastemona sumatrana
developing and
developing seeds, showing aril,
view,
x
-10-12:
55.
330
seed
aril,
3.
seed
respectively.
15:
-
=
vascular
=
17-24. Stemona
longitudinal
and
coats,
a
nuclear
aril
nucellar
tissue,
of fruit with
small
SEM).
endotesta and
cell
bundle
raphal
wall
layer,
14.
and
h
=
a
Group
tegmic remains,
developing
seed
210
and
x
of
16: Cross section
-
endosperm,
hilum, m
of
seed lateral
thickening,
wall
x
8:
-
Developing
=
80.
x
—
micropyle,
a =
r
=
raphe.
seeds
outer
x
9:
-
seeds,
(LM).
17
-
endosperm stage,
180,
x
20.
showing
of endotestal
development,
developing seed during
x
Longitudinal sections of
exotegmic
the
showing multiplicative
adjacent
tion of
=
developing
during
14:
detail
cells,
ex
bundleof
of funicle/raphe showing
seed
layer,
tuberosa
sections
13 &
section
endotestal
wall
endotegmic
v
Cross
mature seeds
micropyle,
of the seed coat
-
showing
coat
showing U-shaped
en
raphide cell,
Plate
Cross sections
200 respectively.
x
and mature
coat
x
x
110, x 650,
funicle and
x
100.
&
30.
x
18: Transmedian
20-23:
-
19:
-
Cross
Cross
sections
of the
integument, development
360,
x
185,
the cellularization
and
90
x
of the
and median
section at the level
respectively.
-
20.
endosperm, x
of
developing
ridges, tegmen
24:
—
Cross
a
=
sec-
aril,
v
=
vascular bundle.
Plate 4.
25-31.
half
section of the
28
&
29:
tegmen,
Detail
Plate
5.
x
37:
x
the
fruit
and
30
and
ridge,
with
8 and
Aril,
x
detail
x
x
x
—
i
showing tegmic
ovules
of the
respectively.
38 &
39:
remnants.
-
25:
-
—
it
=
&
x
Longitudinal
30.
-
and
layer
aril,
zone,
section
8
x
x
section
12.
and
(LM
through
vascular
v =
and
33 &
cross
and
x
-
through
26 &
the
27: Cross
25 respectively.
-
longitudinal section showing 2-layered
36: Seed coat
view
inner
of
Cross
space,
and seeds
aril,
35
Sagittal
detail
30:
-
intercellular
=
australiana
7
-
(LM).
showing preformed rupture
130 respectively.
160.
development
18.
mature seeds
seed, showing embryo, endosperm
section of the seed coat and
Stemona
placenta
view,
of
Cross
of a
32-39.
australiana
Stemona
micropylar
SEM).
ridges,
testa, en
-
34: Mature
section,
=
x
x
the
raphe,
x
40.
-
31:
bundle.
30
32: Ovules
and
220
x
and
endotegmen.
on
lateral
seeds
110
x
the
and
basal
raphal
respectively.
740
-
respectively,
510\1
BLUMEA
Plate
1
VOL.
36,
No.
(Figs. 1—7; legend
2,
1992
on page
509)
F. Bouman
& N. Devente:
Plate
2
Ovules
and
seeds
(Figs. 8—16; legend
in
Stemona
on page
509)
and
Pentastemona
511\2
512\3
BLUMEA
Plate 3
VOL.
36,
No.
(Figs. 17—24; legend
on
2,
1992
page
509)
F. Bouman
&
N. Devente:
Plate
4
Ovules
and
seeds
in
(Figs. 25—31; legend
Stemona
on page
and
509)
Pentastemona
513\4
514\5
BLUMEA
Plate
5
VOL.
36,
No.
(Figs. 32—39; legend
on
2,
1992
page
509)