1. Gymnospe
rms
“The pine stays green in winter...wisdom in hardship.”
Western Mindanao State University
College of Science And Mathematics
Biology and Natural Sciences Department
BotLec 160- Plant Systematics

2. Introduction
• Gymnosperm (DZHIM-no-sperm) is an informal term for all seed plants that have exposed
ovules so that pollen enters the micropyle. The term is derived from two Greek roots
that mean naked (“gymnos” -γσμνός) and seed (“sperma” -σπέρμα).
• The gymnosperms and angiosperms together compose the spermatophytes or seed
plants. By far the largest group of living gymnosperms is the
conifers (pines, cypresses, and relatives), followed by cycads, Gnetophytes
(Gnetum, Ephedra and Welwitschia), and Ginkgo (a single living species).
• The seed, one of the most marvellous products of evolution, is so complex that all seed
plants must be monophyletic, as evidenced by its vegetative tissues (e.g. stems) (Chaw et
al., 2000).
• Their naked condition stands in contrast to the seeds and ovules of flowering plants
(angiosperms), which are enclosed within an ovary.
• Gymnosperm seeds develop either on the surface of scales or leaves, often modified to
form cones, or at the end of short stalks as in Ginkgo.
• There are more than 1000 extant or currently living species of Gymnosperms in 88 plant
genera belonging to 14 plant families.

3. Characteristics
EVOLUTION
• Fossil record estimates indicate that gymnosperms must have evolved approximately 300 million
years ago from non-seed producing ancestors of the extinct division of Progymnospermophyta,
which were fern-like in appearance.
• Considering the relatively small number of living gymnosperms (about 720 species in 65 genera),
they are remarkably diverse in their reproductive structures and leaf types.
• not requiring water for sperm to swim in to reach the egg. Movement of pollen is air-borne.
Consequently, most gymnosperms produce huge amounts of pollen.
• Gymnosperms have major economic uses. Pine, fir, spruce, and cedar are all examples of conifers
that are used for lumber. Some other common uses for gymnosperms are soap, varnish, nail
polish, food, gum, and perfumes.

4. As land-dwelling plants developed further past ferns, several
modifications were developed for water conservation. These included:
• Gametophytes reduced; dependent on sporophyte. Sporophyte independent.
• Swimming sperm was replaced by dispersal of the whole male gametophyte
(pollen) by wind or insects. However, pollen contains sperm or at least
sperm nuclei.
– Pollination—transfer of male gametophytes to the female plant. This still must be followed by
fertilization of the egg by a sperm nucleus which is produced by the male gametophyte.
• Seeds came into being.
• Two categories of seed-bearing plants are recognized:
the Gymnosperms (gymno = naked; sperma = seed), in which the seeds
develop on the surface of the reproductive structures (thus also called the
“naked-seed plants”) such as the cones in pine, and the Angiosperms (angio =
vessel, receptacle, container), in which seeds develop within a specialized
structure, called an ovary, on the adult sporophyte (also called the “flowering
plants”).

5. Representative Species

6. Origin and History
• Ideas about the ancestry of modern gymnosperms are suggested by the fossil record.
• PROGYMNOSPERMS (DIVISION Progymnospermophyta)
• Most likely the ancestors of the first plants that had seeds.
• Middle Devonian-Early Carboniferous period (ca. 360-310 mya)
• Treelike or shrub like resembling those of seed plants as well as the seedless vascular plants.
• DIVISION Pteridospermophyta
• Seed ferns.
• Late Devonian Period
• Became so abundant during the late Carboniferous period---Age of Ferns (Age of seed Ferns)
• Did not evolved from ferns! They are not just ferns with seeds! The seed ferns probably evolved
from the progymnosperms along an evolutionary line that has no modern descendants.
• DIVISION Cycadeoidophyta
• Superficial resemblance to Cycads
• Jurassic Period—Age of Cycads (Age of Dinosaurs)
• Extinct—end of Cretaceous Period (Dinosaurs extint) but Cycads still alive
• Differ from other gymnosperms (living or extinct) by having bisporangiate strobili—ovules and
microsporangia are on the same strobilus.

7. Phylogenetic Relationship
• Two of the most thorough studies of seed-plant phylogenies presented in cladogram:
• Peter Crane (Field Museum of Natural History, Chicago)
• James Doyle (University of California, Davis) and Michael Donoghue (Harvard University)
• Both used fossils as much as possible, although comparable characters of fossil and living plants
are often unknown because of the incompleteness of the fossil record.
Hypotheses differ in the selection
of the characters and the
significance placed on them for
inferring ancestor-descnedant
relationship.
Flowering plants are closest to
gnetophytes among extant
gymnosperms.

8. Division
Coniferophyta

9. Coniferophyta: Introduction
• Conifer
– Latin ; conus (cone) and ferre (to bear), meaning the one that bears (a) cone(s).
• The conifers, Division Pinophyta, also known as
Division Ferophyta or Coniferae, are one of 13 or
14 division level taxa within the Kingdom Plantae.
• They are cone-bearing seed plants with vascular tissue;
• All extant conifers are woody plants, the great majority
being trees with just a few being shrubs.
• Typical examples of conifers include cedars, Douglas-
firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, re
dwoods, spruces, and yews.
• The division contains approximately 7 families, 68 genera, and
630 living species

10. Characteristics
• All living conifers are woody plants, and most are trees, the majority having monopodial growth
form (a single, straight trunk with side branches) with strong apical dominance.
• The size of mature conifers varies from less than one meter, to over 100 meters.
• The world's tallest, thickest, and oldest living trees are all conifers.
– The tallest is a Coast Redwood (Sequoia sempervirens), with a height of 115.55 meters
– The thickest, or tree with the greatest trunk diameter, is a Montezuma Cypress (Taxodium
mucronatum), 11.42 meters in diameter.
– The smallest is the pygmy pine (Lepidothamnus laxifolius) of New Zealand, which is seldom taller than
30cm tall when mature.
– The oldest is a Great Basin Bristlecone Pine (Pinus longaeva), 4,700 years old. Conflicting sources
claim that the largest tree by 3 dimensional volume is either: a Giant Sequoia (Sequoiadendron
giganteum), with a volume 1486.9 cubic meters or a Ficus Benghalensis named Thimmamma
Marrimanu with volume unspecified.
• Many conifers have distinctly scented resin, secreted to protect the tree against insect infestation
and fungal infection of wounds. Fossilized resin hardens into amber.

11. • Primary vascular structure is a eustele. Vascular cambium allows secondary growth.
• Xylem is composed entirely of tracheids and wood is generally parenchyma poor and thus pycnoxylic
• As the name implies, the conifers are called “conifers” because they have cones. In this case, "cone" is a
colloquial term for a woody strobilus. As with other strobili we have studied, those of conifers are derived
from sporangia-bearing branch systems that have been modified.
• The sporophyte is heterosporous; the tiny gametophyte are nutritionally dependent upon the sporophyte.
• Most conifers are monoecious, all are wind-pollinated. Conifer seeds develop inside a protective cone called
a strobilus.
• The male cones have structures called microsporangia that produce yellowish pollen through meiosis.
Pollen is released and carried by the wind to female cones. Pollen grains produce pollen tubes, much like
those of angiosperms. When a pollen grain lands near a female gametophyte, it undergoes fertilization of the
female gametophyte.
• Alternatively, the gymnosperm male gametophytes are carried by wind to a female cone and are drawn into a
tiny opening on the ovule called the micropyle. It is within the ovule that germination occurs. From here, a
pollen tube seeks out the female gametophyte and if successful, fertilization occurs. In both cases, the
resulting zygote develops into an embryo, which along with its surrounding integument, becomes a seed.
Eventually the seed may fall to the ground and, if conditions permit, grows into a new plant.

12. • Many conifers are evergreen, that is they retain their leaves in winter.
• The leaves are needle-shaped. In the majority of conifers, the leaves are arranged spirally.
• Leaf size varies from 2 mm in many scale-leaved species, up to 400 mm long in the needles of some pines
(e.g. Apache Pine , Pinus engelmannii).
• five genera (Larix, Pseudolarix, Glyptostrobus, Metasequoia and Taxodium) are deciduous, shedding the
leaves in autumn and leafless through the winter.
• The seedlings of many conifers, including most of the Cupressaceae, and Pinus in Pinaceae, have a distinct
juvenile foliage period where the leaves are different, often markedly so, from the typical adult leaves.
• Do not form flowers or fruits

13. Seeds
• Consist of an embryo
• Stored food
• Seed coat
– Modern seed plant the ovule consist of a nucellus
envelope by one or two integuments with a micropyle
(apical opening)
– When fertile the nucellus contains a megagametophyte
composed of nutritive tissue and archegonia
– After fertilization the integuments develop into a seed
coat; a seed is formed

14. Characteristics of seed plants:
A. Megasporophylls
B. Heterospory
C. A reduced megagametophyte
retained within the megaspore
D. A megaspore retained within a
fleshy megasporangium called a
nucellus
E. Pollen - a structure which carries
the male gamete to the female
gamete
Seed plants do not require water
for fertilization

15. Two Types of Cones
Staminate and Ovulate

16. Staminate Cones
The pollen-producing
cones
Small, green, and
inconspicuous near
the tips of the
branches
Shed after the pollen
season is over

17. Ovulate Cones
The seed-producing cones
Larger than staminate
cones
Size range: 1-2 inches
Woody structures
consisting of layers of
cone scales
Seeds develop between the
cone scales
Seeds are generally winged

18. Evolution of an ovule
• Retention of the megaspores
within the megasporangium
(fleshy nucellus)- the
megasporangium no longer
releases the spores
• Reduction of megaspore
mother cells to one functional
megaspore in the
megasporangium
• Formation of an endosporic
(within the wall)
megagametophyte that is no
longer free-living- retained
within the megasporangium

19. Evolution of an ovule
• Development of the embryo (young
sporophyte) within the megagametophyte
retained within the megasporangium

20. Evolution of an ovule
• Formation of an integument that
completely envelops the megasporangium
except for the micropyle
• Modification of the apex of the
megasporangium to receive microspores or
pollen grains

21. Evolution of seeds
A. The seed habit arose by 365 million
years ago via fusion of vegetative
tissues around the megasporangium
1. This additional protective layer is
called an integument
2. The integument has a small
opening, the micropyle, through
which fertilization takes place
3. Ovule = an integumented
megasporangium
4. Following fertilization the
integument will become the seed
coat

22. Pine Tree Life Cycle
• Tree produces cones
• Pollen is carried by the wind from staminate cones to
ovulate cones
• Pollen lands on the open scales of the ovulate cone
• The scales then close tightly (in many pines the cone
begins to point downward
• Ovum is fertilized
• When the seeds are mature and environmental conditions
are right, scales open and release seeds

25. Representatives
For objectivity, the figure on the left shows the different FAMILIES
under Order Pinales of the Class Pinopsida, and Division
Pinophyta or Coniferophyta. Note that the Pinophyta was named due
to the abundancy of Pines among conifers. Taxonomically speaking,
the different families under Order Pinales are as follows:
 Pinaceae
 Araucariaceae
 Podocarpaceae
 Sciadopityaceae
 Cupressaceae
 Cephalotaxaceae
 Taxaceae
From: http://en.wikipedia.org/wiki/Pinophyta

26. Pinaceae: The Pine family
• Resinous and evergreen trees or rarely shrubs growing
from 2 to 100 m tall, comprising about 9 genera and 225
species found mostly in temperate regions of the Northern
Hemisphere.
• The leaves are spirally disposed and are linear and
needlelike.
• The male or microsporangiate strobili are small, terminal, or
more often clustered along the stem axis, and consist of many
papery microsporophylls, each with two microsporangia on
the lower surface.
• The pollen grains typically have two, bladderlike wings.
• The female cones or megasporangiate strobili are woody and
often large, consisting of many ovuliferous scales, each with a
pair of adaxial ovules and a more or less distinct subtending
bract.
• Example species:
– Abies pinsapo, Spanish fir.
– Cedrus atlantica, Atlantic cedar. This species has short lateral shoots with closely
spiralled leaves. Both male and female cones are terminal on these short spurs.
– Cedrus deodara, Note that 2 winged seeds separate from each ovuliferous scale.
This genus is one of the exceptional ones for the family in that the cones
disintegrate while remaining on the tree. Nearly all of the scales have already
abscised from the axis of the cone.

27. Araucariaceae: The Aracauria Family
• The Araucariaceae are monoecious or dioecious trees
comprising two genera and about 30 species of the
Southern Hemisphere.
• The leaves are opposite or spirally arranged and are
needlelike to broad.
• The male or microsporangiate strobili are axillary or
terminal, comprising many spirally arranged
microsporophylls, each bearing 5-20 linear, pendant
microsporangia on the lower surface.
• The pollen grains lack wings. The female or
megasporangiate strobili are generally large and somewhat
woody, with numerous spirally disposed ovuliferous scales,
each fused with its bract and bearing a single median ovule
on the upper surface.
• Representative species:
– Araucaria araucana, monkey puzzle tree
– Araucaria columnaris, Cook pine.

28. Podocarpaceae: The Yellow-wood family
• large family of mainly Southern Hemisphere conifers, comprising
about 156 species of evergreen trees and shrubs. It contains
19 genera
• Native to Japan and Southern China, and commonly referred to as
Japanese Yew,
• Podocarpus is a tough, adaptable tree that is a very popular plant for
screens and hedges. Podocarpus has a dense growth habit.
• Its needle-like leaves are dark green above and paler beneath and
reach five inches in length and about one forth of an inch in width.
• Fertilized female cones produce attractive, edible, berry-like, purplish
fruits that ripen over the summer.
• Podocarpus is an evergreen, cold-hardy, drought-tolerant plant.
Showing best growth and form in full sun, Podocarpus will also grow
in shade but will grow more slowly and have a looser appearance. It
will tolerate a variety of well-drained, acidic soils; however, it does not
perform well on wet soils and may become yellow.
• Representative Species:
– Podocarpus macrophyllus. Note developing naked seed on fleshy "receptacle"
– Parasitaxus ustus. This monotypic genus from New Caledonia represents the
world's only known parasitic gymnosperm.

29. Sciadopityaceae: The Umbrella-pine family
• Sciadopitys verticillata, koyamaki, or Japanese umbrella-
pine, is a unique conifer endemic to Japan. It is the sole
member of the family Sciadopityaceae and genus
Sciadopitys, a living fossil with no close relatives, and
known in the fossil record for about 230 million years.
• Its genus name comes from the Greek prefix sciado-
meaning "shadow" and pitys, meaning "pine"; the specific
epithet means "with whorls".
• It is an evergreen tree that can grow 15-27m tall, with brown
main shoots bearing whorls of 7–12 cm long flexible green
cladodes that look like, and perform the function of
leaves but are actually composed of stem tissues;
occasionally, a cladode will be forked and produce a bud in
the 'v' of the fork. The cones are 6–11 cm long, mature in
about 18 months, and have flattish scales that open to
release the seeds.
• It is a very attractive tree and is popular in gardens, despite
its slow growth rate.

30. Cupressaceae: The Cypress family
• The Cupressaceae are monoecious or dioecious trees or
shrubs which include 27–30 genera (17 monotypic), which
include the junipers and redwoods, with about 130–140 species
in total.
• The leaves are usually scale-like, and are opposite and
decussate, or whorled.
• The male or microsporangiate strobili are small and
inconspicuous, axillary or terminal, usually comprising only
a few microsporophylls, each with 3-6 or more
microsporangia. The pollen grains lack wings.
• The female or megasporangiate strobili are small, with 1-12
ovuliferous scales, each fused with its bract and bearing 2-
12 ovules. The scales may be flat and imbricate, peltate, or
connate. The female cone is woody or sometimes fleshy
and berrylike.
• Representative species:
– Cupressus macrocarpa, Monterey cypress. A spreading crown like that seen
here is found in many species of this family. This species has female cones
with woody, peltate scales. Note the low number of scales per cone.
– Cupressus sempervirens var. stricta., Italian cypress.
– Juniperis sp., juniper.

31. Cephalotaxaceae: The Plum-yew family
• Small grouping of conifers, with three genera and about 20
species, closely allied to the Taxaceae
• These are much branched, small trees and shrubs.
• The leaves are evergreen, spirally arranged, often twisted at
the base to appear 2-ranked. They are linear to
lanceolate, and have pale green or white stomatal bands on
the undersides.
• The plants are monoecious, subdioecious or dioecious. The
male cones are 4-25 mm long, and shed pollen in the early
spring. The female cones are reduced, with one to a few
ovuliferous scales, and one seed on each ovuliferous scale.
• As the seed matures, the ovuliferous scale develops into
a fleshy aril fully enclosing the seed. The mature aril is
thin, green, purple or red, soft and resinous.
• Each ovuliferous scale remains discrete, so the cone
develops into a short stem with one to a few berry-like seeds.
They are probably eaten by birds or other animals which then
disperse the hard seed undamaged in their droppings, but
seed dispersal mechanisms in the family are not yet well
researched.
• Representative species:
– Amentotaxus argotaenia
Amentotaxus assamica
– Cephalotaxus fortunei
Cephalotaxus griffithii

32. Taxaceae: The Yew family
• Called the yew family, is a coniferous family which
includes seven genera and about 30 species of plants, or
in older interpretations three genera and 7 to 12 species.
• They are many-branched, small trees and shrubs.
• The leaves are evergreen, spirally arranged, often
twisted at the base to appear 2-ranked. They are linear to
lanceolate, and have pale green or white stomatal bands
on the undersides.
• The plants are dioecious, rarely monoecious. The
male cones are 2–5 millimetres (0.079–0.20 in) long, and
shed pollen in the early spring.
• The female cones are highly reduced, with just one
ovuliferous scale and one seed. As the seed matures, the
ovuliferous scale develops into a fleshy aril partly
enclosing the seed. The mature aril is brightly coloured,
soft, juicy and sweet, and is eaten by birds which then
disperse the hard seed undamaged in their droppings.
However, the seeds are highly poisonous to humans,
containing the poisons Taxine and Taxol
• Representative Species:
– Torreya californica. In this species the seed is entirely enclosed in a fleshy aril.
In other members of the family the aril forms a fleshy cylinder that only
partially envelops the otherwise naked seed.

33. Noteworthy Conifers: Douglas-fir
The Douglas-fir, named for David
Douglas, a 19th century Scottish
botanist. Great strength, stiffness
and moderate weight make it an
invaluable timber product said to be
stronger than concrete. Averaging up
to 200' in height and six feet in
diameter, heights of 325' and
diameters of 15' can also be found.
Provide more than ¼ of the timber cut in the U.S.

34. Noteworthy Conifers: Sequoia
In central California
Some are among the oldest
living things on earth (2,000
– 3,500 years)
273 feet tall
84 feet circumference
Bark 1 foot thick

35. Noteworthy Conifers:
Bristlecone Pines
The oldest living bristlecones are found in
the White Mountains of California. The
oldest known living tree, discovered in
1957, is a 4,723-year-old patriarch
named Methuselah.
The oldest bristlecones are more than
4,000 years old. Egypt’s pyramids were
under construction when these trees
were seedlings!

36. Noteworthy Conifers:
Coast Redwood
Redwood trees are the tallest living things on earth.
Some grow more than 350 feet tall.

37. CladisticsDIVISION CONIFEROPHYTA

39. PINACEAE
ARAUCACEAE
PODOCARPACEAE
SCIADOPITYACEAE
CUPRESSACEAE
CEPHALOTAXACEAE
TAXACEAE
GINKOPHYTA
Division Coniferophyta Cladogram