Gymnosperm is from the Greek “gymnos” naked, and “sperma” seeds. They are groups of vascular plants that reproduce by means of an exposed seeds or ovules. They are phanerogams according to A. W. Eichler.

1. Done by: TheRock Peterson

2. Group 9

3. Presentation Outline
• Overview of Gymnosperms
• Evolution
• Characteristics of Gymnosperms
• Comparing the sporophyte-gametophyte relationship in seedless plants and
Gymnosperms
• Life cycle of a pine
• The four phyla of Gymnosperms and their Importance

4. Overview of Gymnosperms
• Gymnosperm is from the Greek “gymnos”
naked, and “sperma” seeds
• Gymnosperms are groups of vascular
plants that reproduce by means of an
exposed seeds or ovules
• They are phanerogams according to Eichler
• They include 83 genera, 12 families and
1,080 living species

5. Overview Cont’d…
• They include four
phyla;
• Coniferophyta
(Conifers)
• Pine, Spruce,
redwood…
• Cycadophyta (Cycads)
Fig 1.1 Cycad
Conifer

6. Overview Cont’d…
• Ginkgophyta( ginkos)
• Ginkgo biloba
• Gnetophyta/Gnetopsida
• Ephedra
Ginkgo biloba
Witwhicher

7. Characteristics of Gymnosperm
• Most gymnosperms are evergreen with
a small percentage that tends to be
deciduous
• Most are trees (woody stem) Eg:
redwood A few are shrubs
• Seeds are not borne on flower or in fruit
as angiosperms
• They are paraphyletic taxonomically
• They have a root system similar to a
dicot stem

8. Characteristics Cont’d…
• Also called spermatophytes
• Most possess needle- like leaves
• Have vascular tissues
• Tracheids (are present in all)
and vessel elements (present
only in gnetophytes)

9. Needle-like leaves of Some Gymnosperms

10. Characteristics Cont’d...
• They have cone as their reproductive
structure (strobili-strobilus)
• Two types of cones: pollen cone
(pollen) and ovulate cones (eggs)
• They form spores: micro-megaspores
are produced by sporophyte
generation
• These gymnosperms include the tallest
and oldest trees
Ovulate cone
Pollen cone

11. Characteristics Cont’d...

12. Representation of Gymnosperms

13. General Characteristics: Habitat
• Gymnosperms occupy a large area of the
earth surface
• Some are xerophytic
• Some live in equatorial regions
• Concentrated in forests and woods
• They can also grow at high altitudes
• Lithophytes
• Psammophytes

14. Selective Advantages of Seeds In Seed Plants
• Seeds include food for developing
embryo and germinating seedling
• They provide nourishment for the
embryo during dormant state
• Attract seed eating animals which
destroys some seeds, but distribute
others
• Seed coat serves as a barrier against
bacterial and fungal decay

15. Evolution of Gymnosperms
• Gymnosperms are believed to have evolved from the paleozoic to the mesozoic
eras
• There are 3 groups of extinct plants that played important roles in the evolution
of modern gymnosperms
• They are progymnosperms, aneurophytales , and a groups of primitive
gymnosperms: archaeopteridales
• In middle devonian period, progymnosperms arose from the trimerophytes
which were extant until the lower carboniferous period

16. Evolution Cont’d…
• Progymnosperms gave rise to aneurophytales that gave rise to
pteridosperms and archaepteridales
• Aneurophytales were homosporous, producing many identical spores
and had three dimensional branching
• Unlike the progymnosperms, the pteridosperms produced seeds
appearing in the late devonian period

17. Evolution Cont’d…
• Pteridosperms were the first seed plants, with integuments
protecting ovules to various degrees
• Another extinct group of Pteridosperms are the Bennettitales, which
resemble present cycads.
• The Archaeopteridales may have given rise to the Cordaitales and the
Voltziales
• The Archaeopteridales arose from the Aneurophytales

18. Evolution Cont’d...
• The cordaitales were trees and shrubs during the carboniferous and
permian periods both in swamp and dry land which had slender leaves.
• They also had vascular cambium tissues and ovulate cones.
• The cordaitales apparently gave rise to the phylum ginkgophyta, which
persists to present day and others which have relatives to cycadophyta,
gnetophyta and coniferophyta.
• Voltziales is an extinct order of trees that gave rise species related to
modern conifers.

19. Mode of Nutrition
• Gymnosperms are
photosynthetic
• Symbiotic

20. Distinguishing Features between Angiosperm
and Gymnosperm
• Pollination
• Angiosperms rely on wind and animals
• Gymnosperms rely on wind
• Time interval between pollination and fertilization
• In Angiosperms it occurs simultaneously
• Gymnosperms pollen sits within the cone for up to 15 plus months before
fertilization

21. Distinguishing Features between Angiosperm
and Gymnosperm
• Double fertilization
• In Angiosperm one sperm fertilizes egg, the other combines to form an
endosperm
• Double fertilization in Gymnosperms is absent
• Fruits
• Angiosperms produce fruit, animals are used as agents of pollination
• Gymnosperms form seeds without fruits

22. Comparing The Sporophyte-gametophyte Relationship
In Seedless Plants and Gymnosperms
Seedless plants
 Sporophyte depends on the
gametophyte throughout its
life.
 Exosporic development
 Homosporous, with one
type of spore produced by
one type of sporangium.
Gymnosperms
 Seed can germinate and
grow into an independent
sporophyte.
 Endosporic development
 Heterosporous; producing
two types of spores:
microspore and megaspore.

23. Comparing the sporophyte-gametophyte relationship in seedless
plants and Gymnosperms

24. Reproduction In Gymnosperms
• Gymnosperms were the most dominant phylum is the mesozoic era.
• The life cycle in gymnosperms involves an alternation of generation.
• Dominant sporophyte in which the female gametophyte and
reduced gametophytes resides.
• The male and female reproductive organs can be formed in cones or
strobili
• The male and female sporangia are produces either in the same
plant or on separate plants`

25. Reproduction Cont’d…
• Sporangia are either monoecious or dioecious
• Diploid sporophyte stage in most of their life time (cycle), with a haploid
gametophyte that is short lived
• Two spore types: microspores and megaspores are typically produced in
the pollen cone or ovulate cone respectively.
• There are two main modes of fertilization found in gymnosperms
• Male gametophyte and female gametophyte

26. Pine Life Cycle

27. Classification of Gymnosperm
• There are four surviving phyla of gymnosperm
• They vary greatly in appearance and habitat
• They are grouped into:
• Conifers, Cycads, Ginkos and Gnetophytes
• The four phyla of living gymnosperms are of separate clades or
lineages, unlike the angiosperms, which are a monophyletic, single
lineage

29. Phylum Coniferophyta
• The Coniferophyta division contains conifers
which has the greatest variety of species
among gymnosperms
• Most conifers are evergreen (they retain their
leaves throughout the year)
• They include some of the largest, tallest and
oldest trees on the planet
• Examples of conifers include The familiar
pines, firs, spruces, yews, hemlocks, and
junipers
• The word conifer means ‘cone-bearer’, it is a
distinct characteristics common to conifers.

30. Coniferophyta Cont’d...
• They have needle-like leaves
• needle leaf conifers also have a waxy coat on the
leaf surface to help prevent water loss in the dry
climate
• this taxon includes secondary growth and the
production of protective buds
• They also have a significant amount of intermodal
elongation which allows them to grow faster than
many other plants.
• Consists of 50 genera and 550 species

31. Coniferophyta Cont’d...
• Not all of the conifers resemble the needle‐leaved pines in appearance or
length of time to complete the sexual reproductive cycle
• Some conifers are deciduous, such as larch ( Larix), bald cypress (
Taxodium), and the dawn redwood (Metasequoia)
• They have vascular tissues. Meristems and other plant tissues
• Cones house their reproductive structure

32. Coniferophyta Cont’d...

34. Classification of Cycadophyta
o Kingdom: Plantae
o Phylum: Cycadophyta
o Class: Cycadopsida
o Order: Cycadales
o Family: Cycadaceae
o Genus: Cycads

35. Phylum Cycadophyta
• Cycads are found in tropical forest
and sub-tropical regions
• Second largest group of
gymnosperms consisting of 11
genera and 140 species
• Pseudoparasitic which are
epiphytic
• Evergreen gymnosperms

36. Cycadophyta Cont’d...
• Characterized by large croon of
compound leaves
• Palm like or fernlike
• Dioecious
• Found in subtropical and tropical
parts of the world
• Grow in semi-desert climates and in
sand
• Carry on symbiotic relationship with
bacteria

37. Cycadophyta Cont’d...
• These microbes produce toxins or poisons that accumulate in seeds
• These toxins are thought to provide protection against bacteria or
fungal parasite
• seeds can be dangerous to humans or animals if they are ingested.
• Seeds are propagated by agents of pollination mainly wind

38. Insect Sitting On Cone To Pollinate

39. PHYLUM GINKGOPHYTA

40. Phylum Ginkgophyta
• Have only one extant species, named Ginkgo
biloba
• Ginkgo comes from the Chinese word
meaning “Silver apricot” (gin=silver, kyo=
apricot).
• Biloba comes from the Latin meaning “double
leaves” (bi=double, loba= leaf.
• G.biloba is one of the oldest living tree
species, over 300 million years ago. Individual
tree can live for over 1000 years.
• Only one extant specie

41. Phylum Ginkgophyta
• Leaves are unique among
seed plants, fan-shaped
with veins radiating out into
the leaf blade
• Ginkgo leaves are bi-lobed,
tough and more resistant to
decay than other leaves

42. Ginkgophyta Cont’d...
Seeds
• Have fleshy coats, but they are
not like the true fruits of
Angiosperms
• They are attractive in
appearance, but contains
butanoic acid and have a bad
odor like rancid butter
• Ginkgos are dioecious

43. Ginkgophyta Cont’d..
• Vascular system of ginkgos, and also
conifers, are different to that of
flowering plants
• Flowering plants have a series of
tube-like cells to conduct water.
• Ginkgos have connecting cells with
tiny perforations
• These are valves(perforations) that
close when water is in short supply so
that turgidity is preserved
• Ginkgos have a tendency to put out
suckers from the ground

44. Ginkgophyta Cont’d...
• Older trees sometimes also have odd
downward growths, called Chichi
• They grow from a damaged stem or by
putting out new shoots from the ground
• When these growths hit the ground they
can start growing new roots and
eventually form into a new tree
• this seems to be a form of reproduction
for when the main tree is coming to the
end of its life, or when there are no
females around.

45. Example of Chichi on Ginkgo

46. Phylum Gnetophyta

47. Phylum Gnetophyta
• Gnetophyta are small group of vascular seed plants composing one of the
four phylum of gymnosperm
• They include 70 species divided into three: Ephedra, Gnetum, and
Welwitschia
• They have more angiosperm like features than any other gymnosperms
• Welwitschia and Gnetum are similar to flowering plants: not having
archegonia, and some species of Ephedra and Gnetum are the only plants
to go through double fertilization.

48. Phylum Gnetophyta: Gnetum species
• Gnetum are mostly vines or shrubs
• 30 species
• They are found in South Asia,
Tropical Africa, and Amazon basin
• Their leaves are broad and
resemble flowering plants
• Their seeds are eaten
Gnetum seeds
Gnetum specie

49. Phylum Gnetophyta: Ephedra Species
• Ephedra known as Mormon tea or
joint firs
• 30 species
• They are found in Northern Mexico
and South Western US
• Strobili usually emerge from the
axils of leaves
• Some species undergo double
fertilization

51. Phylum Gnetophyta: Welwitschia Species
• Welwitschia contains only one
species(Welwitschia mirabilis)
• They are found in South
Western Africa
• They survives in extremely
drought
• Their leaves grow perennially
and they are larger
• They have the largest leaves in
the plant kingdom

52. Welwitschia Species In A Xerophytic
Environment

53. Importance of Gymnosperms

54. Importance of Gymnosperms
• They importance of gymnosperms are categorized into the following group
 Industrial value
 Ornamental value
 Food value
 Medicinal value
 Timber value
 Source of oil

55. Importance of Gymnosperms
Food Value
• Cycads are good source of starch, that is
obtained from Cycas rumphi , which is
processed into flour
• Seeds of Pinus gerardiana and Gnetum
seeds are edible known as chillgoza
• Kaffir bread is a type of bread prepared
from the stem pith of Encephalatos
• Young leaves of cycas are cooked as
vegetables in some parts of the world

56. Importance of Gymnosperms
Medicinal value
• Paclitaxel (PTX) sold under the name Taxol, used
for chemotherapy against cancer
• Ephedrine is an alkaloid extracted from the
Ephedra. It is used in the treatment of asthma,
cough, cold, bronchitis.
• Juice from the young leave of the phylum Cycas
revoluta is used for curing blood vomiting.
• Cycas guns: is an antidote against snake bite and it
is also used to cure malignant ulcer.

57. Importance of Gymnosperms
Timber value
• Gymnosperms are a good source of timbers; they
are mainly softwood which is beneficial in
furniture settings and construction purposes
• The woods from conifers are resistant to insects
and fungus
• Woods from Gymnosperms are also durable and
of light weight
• A specie of gymnosperm called Agathis australis
is the largest timber producing tree in the world
• Plywoods and other scented woods are all
products processed from Gymnosperms.

58. Importance of Gymnosperms
Source of Oil
• Edible oil is extracted from the
seeds of Cycas revoluta,
macrozania and many others
• Red cedar wood oil is extracted
from the heartwood of juniperus
virginiana is used in oil
immersion microscopy.
• Oil from Gymnosperms are also
used in deodorants and soaps

59. Importance of Gymnosperms
Industrial value
• Tannins extracted from the
bark of pinus and sequoia are
used in the leather industry
• Newspapers, writing papers,
and printing papers are
prepared from the wood pulp
of pinus, picea and abies

60. Importance of Gymnosperms
Ornamental Value
• Ornamental plants are
plants that are grown for
decorative purposes
• Ginkgo and other pines,
cycads and Gnetum
species used in decoration
of lawn, parks etc..
• Various species of
gymnosperms can also be
grown as Bonsai

61. Importance of Gymnosperms
Gymnosperms
Used as Ornaments

62. In Conclusion:
• Gymnosperms are under the group sub group of plants called the phanerogams
• They are non-flowering, but seed bearing.
• That they are photosynthetic in nature.
• Cycads, conifers, ginkos and gnetophytes are four groups of plants that are closely
related, which forms the four main categories of gymnosperm.
• These categories of plants are useful to mankind both in medicine, food, and the
ecosystem.

63. Reference
• Nabor, Murray W., INTRODUCTION TO BOTANY, Copyright 2004
Pearson Education, Inc., publishing as Benjamin Cummings, 1301
Sansome St., San Francisco, CA 94111
• www.khanacademy.org/science/biology/gymnosperms-in-
plants/discussion/--c3-c4-andcycads/conifers-gneptosida--and-
plants-agriculture
• http://www.svenlandrein.com/systematiccoursepages/gymno

64. •‘Always learn to be a smart student’
-Mr. Fasama H. Kollie
Rocky productions

65. Questions!
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