This document discusses the evolution of conifer cones and seed scales. It describes Stewart and Florin's hypotheses about the origin of ovuliferous scales from modified fertile shoots. Key points include: - Florin proposed that ovuliferous scales evolved from dwarf, ovule-bearing shoots that became highly condensed and modified. - Early precursors like Lebachia and Erniodendron had short fertile shoots in their axils with some sterile and one fertile scale bearing an ovule. - Over time, more scales fused and ovules became adnate to the underside of scales, leading to the modern conifer cone possessing specialized seed scale complexes.

1. SEED SCALE COMPLEX
SEWART
STEWART hypotheses -
Perhaps the Lycopsida form a
gymnosperm because l.s. of
Selaginela megasporangium it
shown megaspore 3 abortive ,
ligule, sporophyll and
megasporangia.
 Sporophyll-bract scale
 Ligules- ovuleferous scale

2.  Megasporangiophyll-cone
They are analogous parts
As for as leaf is concerned –
Lycopodium. clavatum –they
are microsporophyll’s as that
of conifers
Lycopsida- It originate conifer
Filicopsida- It originated
Cycas and Pteridosperm

3. FLORIN
Florin’s hypotheses
(SWEDEN, 1894-1965)
Florin 1951 –ovuliferous scale
is compound structure and not
simple as proposed by
stewart.
Lebachia - Ernetiodendron –
Voltiza – Pseudovolzia –
Olmannia

4. During carboniferous and
permian these plant appeared
and source of coal
FLORIN called is “samen
schoppen komplex” which
means Seed scale complex .

6. Voltziales and the origin of the
ovuliferous scales
Although the evidence from
organography,comparative anatony,and
ontology supports the view that ovulate
cones in the conifers is a compound
strobilous,the phylogenetic origin of the
ovuliferous scales remains to be
explained. The scale is similar to
sporophyll in that it bears ovules, but
its axillary position with reference to a
bract represents a puzziling situation
from an evilutionary point of view, of all
the conflicting and involved theories
that have been proposed during the
past century,the most plausible and
best supported view was advanced by
Florin:
Phylogenitically,the ovuliferous scales
is a highly condensed and modified

7. fertile shoot and hence is not a simple
sporophyll. In other words, the scale
evolved from a leafy, ovule-
bearing,dwarf shoot and its present
simple appearance is the result of the
fusion and specialization of both the
sterile and fertile components of such
an ancestral structure.
The earliest precursors of the
modern
ovulifer
ous
scales
occurre
d in
Lebachi
a and
ernestio
dendron
, two
genera
of voltziales from the upper
carboniferous-permian. In lebachia
piniformis, a eusporangiate or ovulate
cone consisted of a series of helically
arranged, bifid bracts,in the axils which
developed short fertile shoots.usually
all at one of the scale like leaves of the
fertile shoot are sterile. The fertile
scale (termed megasporophyll by some

8. authors) consisted of a stalk and an act
terminal,bilaterally symmetrical ovule
that had the axis of cone.most of the
materials studied by florin(1951) were
impression-compression fossils. Recent
studies of permineralised cones have
supported,in general, florin’s concept of
the early origin of conifers reproductive
structures. A fertile shoot of lebachia
lockardii consisted of twenty five to
thirty sterile scales and one or two
fertile scales at the base of shoot .
there was one terminal inverted ovule
per fertile scale (mapes and
rothwell,1984). Pollen grains have also
been found in the pollen chamber. In
contrast to lebachia,all scales were
fertile in ernestiodedron filiciforme.
Florin termed the fertile shoot in these
and other conifers “seed scale
complexes” and belived they support
the view that the compound
megasporangiate strobilus is the
primary form in the coniferales, with
the exception of the taxales
(taxaceae). The great man regarded the
taxales as having the separate
evolutanory history because of they
lack definable seed cones: this view

9. has been questioned in recent years
(Miller,1977).
Genera from the late permian and
arly part of the mesozoic,illystrate
additional evolutoinary steps towards
the modern day type of ovuliferous
scales in the coniferales . in
pseudvoltzia liebeana, for example, the
fertile shoot consist of five partially
fused scales, forming a dorsiventral
“ovuliferous scales.” The middle lobe
and the two lateral lobes each had a
reflexed ovule, adnate to its base. The
entire ovuliferous scale complex was
fused with the subtending bracts to
about its midpoint; vascular strands to
the ovuliferous scale and
bract,however,were not fused, an
indication that the ovuliferous scales
and bracts probably were not fused in
ancestral type (schweitzer,1963). In the
triassic genus voltzia, the ovuliferous
scale also consisted of five partially
fused scales and three inverted ovules
whose stalks were adnate to the

10. ovuliferous scale.
In summary, the main trends in seed
cone & seed scale evolutoin have been
towards:--
(1)the elimination of all but a few
sterile scales, which became fused into
the so-called ovuliferous scale,
(2)the recurvation of ovules and
suppression of their stalks,
(3)their final incorporation with the
lower adaxial side of the ovuliferous
scales in derived conifers. On the basis
of the ground plan-divergence method
of cladistics,Miller(1982) have proposed

11. a phylogeny of the voltziales and
modern-day families of the coniferales
based upon fourteen characters of the
bract, seed scale complex.
In modern day conifers, evolutionary
advancement in the ovulate cone is
shown by the various degrees of fusion
between the ovuliferous scales and its
sub-tending bracts.throughout the
pinaceae, the bract is only basally
adnate to the scale, whereas these
structure are more or less completely
united in members of the
taxodiaceae,cupressaceae,and
araucariaceae. Comparative studies of
the vascular anatomy of the ovulate
cone in the pinaceae reveal that the
traces which enter the ovuliferous
scale diverge from the stele in
fundamentally the same manner as the
branch traces of an axillary vegetative
shoot in pinus meritima,for example,
Aase(1915) found that a single
vascular strand, with the xylem
oriented towards the adaxial surfaces,
as in a vegetative leaf,extends as a
separate trace into the bract. In
contrast, the branch like vascular
supply of the ovuliferous scale consist
of three ar four traces that diverge at a

12. higher level from the stele:these
strands branch dichotomously in the
scale and form a series of veins with
their xylem oriented towards the lower
surface of the scale. According to
Florin(1951), the so-called “inversion”
of the vascular bundles in the
ovuliferous scale in the pinaceae
indicates its phylogenetically original
radial symmetry. Each of the two
ovules borne on the ovuliferous scales
is vascularised by a single strand
derived as a branch from an adjacent
lateral bundles.
Lemoine-
sebastian(1968,69) has studied the
vasculature of the bracts and
ovuliferous scales of the ovulate cones
of various genera in the Taxodiaceae
and cupressaceae. The bract is
vascularised by a single trace that only
rarely branches in its course through
the appendage. But the pattern of
vasculature of the ovuliferous scales is
usually very complex and varies
acording to the genus. In some genera,
only the single system of inversely
oriented strands is formed: in other
genera, the radial branching of the
strands forms two vascular arcs;an

13. adaxial series of strands with inverted
orientation of the xylem and an abaxial
system comprising normally oriented
bundles. These varied patterns of
vasculature of the ovuliferous scales in
the taxodiaceae and cupressaceae are
of considerable morphological and
systematic interest, but their
phylogenetic significance is an open
qustion; there are however,
recommendations that the two families
should be merged, based upon analysis

14. of numerous morphological characters.

17. Conifer cone possesing seed
scale complex
Mature female Pinus coulteri cone

18. An Aleppo Pine cone
A cone (in formal botanical usage: strobilus, plural strobili) is
an organ on plants in the division Pinophyta (conifers) that
contains the reproductive structures. The familiar woody cone
is the female cone, which produces seeds. The male cones,
which produce pollen, are usually herbaceous and much less
conspicuous even at full maturity. The name "cone" derives
from the fact that the shape in some species resembles a
geometric cone. The individual plates of a cone are known as
scales.
The male cone (microstrobilus or pollen cone) is structurally
similar across all conifers, differing only in small ways (mostly
in scale arrangement) from species to species. Extending out
from a central axis are microsporophylls (modified leaves).
Under each microsporophyll is one or several microsporangia
(pollen sacs).
The female cone (megastrobilus, seed cone, or ovulate cone)
contains ovules which, when fertilized by pollen, become
seeds. The female cone structure varies more markedly
between the different conifer families, and is often crucial for
the identification of many species of conifers.
Female cones of the conifer families
Pinaceae cones

19. Intact and disintegrated fir cones
Young cones of a Colorado Blue Spruce
The members of the pine family (pines, spruces, firs, cedars,
larches, etc.) have cones that are imbricate (that is, with scales
overlapping each other like fish scales). These are the
"archetypal" cones. The scales are spirally arranged in
fibonacci number ratios.
The female cone has two types of scale: the bract scales,
derived from a modified leaf, and the seed scales (or
ovuliferous scales), one subtended by each bract scale, derived
from a highly modified branchlet. On the upper-side base of

20. each seed scale are two ovules that develop into seeds after
fertilization by pollen grains. The bract scales develop first, and
are conspicuous at the time of pollination; the seed scales
develop later to enclose and protect the seeds, with the bract
scales often not growing further. The scales open temporarily to
receive gametophytes, then close during fertilization and
maturation, and then re-open again at maturity to allow the seed
to escape. Maturation takes 6–8 months from pollination in
most Pinaceae genera, but 12 months in cedars and 18–24
months (rarely more) in most pines. The cones open either by
the seed scales flexing back when they dry out, or (in firs,
cedars and golden larch) by the cones disintegrating with the
seed scales falling off. The cones are conic, cylindrical or ovoid
(egg-shaped), and small to very large, from 2–60 cm long and
1–20 cm broad.
After ripening, the opening of non-serotinous pine cones is
associated with their moisture content—cones are open when
dry and closed when wet.[1
This assures that the small, wind
disseminated seeds will be dispersed during relatively dry
weather, and thus, the distance traveled from the parent tree
will be enhanced. A pine cone will go through many cycles of
opening and closing during its life span, even after seed
dispersal is complete.[2]
This process occurs with older cones
while attached to branches and even after the older cones have
fallen to the forest floor. The condition of fallen pine cones is a
crude indication of the forest floor's moisture content, which is
an important indication of wildfire risk. Closed cones indicate
damp conditions while open cones indicate the forest floor is
dry.
Araucariaceae cones
Members of the Araucariaceae (Araucaria, Agathis, Wollemia)
have the bract and seed scales fully fused, and have only one
ovule on each scale. The cones are spherical or nearly so, and
large to very large, 5–30 cm diameter, and mature in 18
months; at maturity, they disintegrate to release the seeds. In
Agathis, the seeds are winged and separate readily from the
seed scale, but in the other two genera, the seed is wingless and
fused to the scale.
Podocarpaceae cones

21. Berry-like Podocarpus cone
The cones of the Podocarpaceae are similar in function, though
not in development, to those of the Taxaceae (q.v. below),
being berry-like with the scales highly modified, evolved to
attract birds into dispersing the seeds. In most of the genera,
two to ten or more scales are fused together into a usually
swollen, brightly coloured, soft, edible fleshy aril. Usually only
one or two scales at the apex of the cone are fertile, each
bearing a single wingless seed, but in Saxegothaea several
scales may be fertile. The fleshy scale complex is 0.5–3 cm
long, and the seeds 4–10 mm long. In some genera (e.g.
Prumnopitys), the scales are minute and not fleshy, but the seed
coat develops a fleshy layer instead, the cone having the
appearance of one to three small plums on a central stem. The
seeds have a hard coat evolved to resist digestion in the bird's
stomach, and are passed in the bird's droppings.
Cupressaceae cones
Juniper "berries", which are used to flavor gin, are actually
modified cones.

22. Giant Sequoia cones
Members of the cypress family (cypresses, arborvitae, junipers,
redwoods, etc.) differ in that the bract and seed scales are fully
fused, with the bract visible as no more than a small lump or
spine on the scale. The botanical term galbulus (plural galbuli;
from the Latin for a cypress cone) is sometimes used instead of
strobilus for members of this family. The female cones have
one to 20 ovules on each scale. They often have peltate scales,
as opposed to the imbricate cones described above, though
some have imbricate scales. The cones are usually small, 0.3–
6 cm long, and often spherical or nearly so, like those of
Nootka Cypress, while others, such as Western Redcedar, are
narrow. The scales are arranged either spirally, or in decussate
whorls of two (opposite pairs) or three, rarely four. The genera
with spiral scale arrangement were often treated in a separate
family (Taxodiaceae) in the past. In most of the genera, the
cones are woody and the seeds have two narrow wings (one
along each side of the seed), but in three genera (Platycladus,
Microbiota and Juniperus), the seeds are wingless, and in
Juniperus, the cones are fleshy and berry-like.
Tetraclinis cones
Sciadopityaceae cones
The cones and seeds of Sciadopitys (the only member of the
family) are similar to those of some Cupressaceae, but larger,

23. 6–11 cm long; the scales are imbricate and spirally arranged,
and have 5-9 ovules on each scale.
Taxaceae and Cephalotaxaceae cones
Berry-like yew cone
Members of the yew family and the closely related
Cephalotaxaceae have the most highly modified cones of any
conifer. There is only one scale in the female cone, with a
single poisonous ovule. The scale develops into a soft, brightly
coloured sweet, juicy, berry-like aril which partly encloses the
deadly seed. The seed alone is poisonous. The whole 'berry'
with the seed is eaten by birds, which digest the sugar-rich
scale and pass the hard seed undamaged in their droppings, so
dispersing the seed far from the parent plant.
Cycadaceae cones
This group of cone-bearing plants retains some types of
'primitive' characteristics. Its leaves unfurl, much like ferns.
There are three extant families of Cycads of about 305 species.
It reproduces with large cones, and is related to the other
conifers in that regard, but it does not have a woody trunk like
most cone-bearing families.
Welwitschiaceae cones
A unique cone-bearing plant in the Order Welwitschiales,
Welwitschia mirabilis is often called a living fossil and is the
only species in its genus, which is the only genus in its family,
which is the only family in its Order. The male cones are on
male plants, and female cones on female plants. After
emergence of the two cotyledons, it sets only two more leaves.
Those two leaves then continue to grow longer from their base,
much like fingernails. This allows it great drought tolerance,
which is likely why it has survived in the desert of Namibia,
while all other representatives from its order are now extinct.

28. REFERENCES:-
Morphology and evolution of
vascular plants
‗ernest m gifford
‗adriance s foster
---seed scale complex in
conifers,430

29. Google –encyclopedia,seed
scale complex