The document discusses gymnosperms, which are plants with naked seeds. It defines gymnosperms as having ovules that are freely exposed and attached to open structures, rather than being protected within closed structures like in angiosperms. The document then covers the distribution, external features, internal features, and reproduction of gymnosperms. It notes that gymnosperms include some of the world's tallest trees and have a variety of habitats, and describes key anatomical aspects like their vascular tissue and cones.

1. Submitted To:- Submitted By:-
Ms. Pooja Simranpreet Kaur
BSC-1st Year
Roll No-111

2. The word gymnosperrm is derived from the Greek words Gymnos
= naked and sperm = seed. That means the plants with naked
seeds The term was used in 300 B.C. by the Greek botanist
Theophrastus for the group of plants with unprotected seeds.
The gymnosperms have their ovules freely exposed and attached
on open megasporophylls whereas the ovules in angiosperms are
protected within the closed megasporophylls (carpel). Therefore,
the gymnosperms are placed under distinct subdivision of
spenuatophyta (phanerogams or seed bearing plants). Goebel
described these plants as "phanerogams without ovary".

3. 1. Distribution and Habit
2. External Features
3. Internal Features
4.Reproduction

4.  The living gymnosperms are widely distributed in the
cold climates of the temperates as well as in the dry and
arid conditions of the tropics. Some gymnosperms
occur even in arctic zones. In India, they are mostly
distributed in hilly areas. Very few gymnosperms,
except sonic cycads. grow in plains of India.
 Living gymnosperms are mostly perennials, xerophytic.
evergreen. arboreal and woody plants. They grow as
woody trees, bushy shrubs or rarely as climbers (e.g.,
Gnetales). None of them are herbs or annuals.

5.  The plant body is sporophyte and differentiated into root. stem and leaves.
 The gymnosperms include world's tallest tree--siquoia (the giant red wood), measuring
125 metres in height and 30 metres in girth. This tree is about 4.000 years old and
found in wood Park of California. The smallest gymnosperm is Zamia pygmia, which has
underground tuberous stem
 The plants possess tap root system formed from the radicle. In some cases the roots
symbiotically associated with algae (e.g., coralloid roots of Cycas) or with fungus (
mycorrhizal roots of Pinus).
 The stem is usually erect and branched (unbranched in Cycads). In most of the species.
woody. The superficial surface of star) shows the presence of characteristic leaf scars.
 Leaves may he monomorphic (i.e., of one kind) or dimorphic (i.e.. of two kinds). When
dimorphic, the folliage leaves are evergreen, simple (Pinus), or compound (Cycas) and
protected by a thick cuticle. The scale leaves arc minute and deciduous.

6.  The roots have &arch or polyarch xylem in vascular cylinder. The
secondary growth occurs.
 In stem the vascular bundles are conjoint, collatcral and open. They
are arranged in ring. Secondary growth occurs by the activity of
cambial ring formed by joining of fascicular cambia and
interfascicular cambia. Annual rings are distinct inmost of
gymnosperms.
 The vessels and wood fibres are absent in the xylem (except in
Gnetales) and the companion cells are absent in phloem.
 In some gymnosperms, the wood is manoxylic (e.g. Cycas) whereas
in others it is pycnoxylic (e.g. Pinus).

7.  The plants are usually heterosporous, i.e., produce two different kinds of spores — the male
microspores and the female megaspores. The spores are borne inside the sporangia.
 The microspores (= pollen grains) are borne inside the microsporangia (= pollen sacs) and the
megaspores (= embryo sac cells) are borne inside the megasporangia (= ovules).
 The development of sporangia is eusporangiate type, i.e., the sporangium develops from group
of initial cells originating from hypodermis.
 The microsporangia are borne on abaxial or lower surface of microsporophylls (= stamens) and
the megasporangia are borne naked on megasporophylls (= carpels). The microsporangia may
be arranged in definite groups called sori (Cycas) or their number may be reduced to two
(Pinus).
 The microsporophylls are aggregated in the form of compact structures called male cones (=
male flowers) and the megasporophylls are usually aggregated in the form of female cones (=
female flowers). In some cases, the megasporophylls are foliar in nature and not aggregated in
the form of cones (e.g., Cycas).

8.  Earlier the members of gymnosperms were placed and
classified among angiosperms. They were not grouped
separately as gymnosperms. But Robert Brown (1827)
separated them from angiosperms and placed under a
distinct group due to presence of unprotected ovules in them.
Since then a large number of classifications were proposed by
various authors from time to time.

9. Gifford and Foster(1989)- divided gymnosperms into seven major taxa (or
divisions) as under
 Division1. Progymnospermphyta
Order I. Aneurophytales
OrderII. Archaeopteridales
 Division 2. Pterdospermophyta
Order I. Pterdospermales
OrderII. Glossopteridales
Order III. Caytonials
 Division 3. Cycadophyta
Order I. Cycadales
 Division 4. Cycadeoidophyta
Order I. Cycadeoidales
 Division 5. Ginkophyta
Order I. Ginkgoales

10.  Division 6. Coniferophyta
Order I. Conferales
Family- Pinaceae
Family- Taxodiaceae
Family- Cupressaceae
Family- Araucariaceae
Family- Podocarpaceae
Family- Cephalotaxaceae
Family- Taxaceae
Order II. Voltziales
Order III. Cordaitales
Division7. Gnetpphyta
Order I Ephedrales
Order II. Gnetales
Order III. Welwitschiales
The classification followed in thi