Spermatophyta is divided into to subdivisions- gymnospermae and angiospermae.
Spematophyta include plants:
a) whose body is differentiated into roots, stem and leaves,b) vascular bundles are well developed , andc) which produce seeds.
Gymnosperms are woody trees with cone like appearance. They bear no flowers, no fruits but bear seeds. The seeds are naked as they are not covered by the fruit wall.
Examples: Pinus, Cycas and Cedrus trees
Angiosperms The angiosperms consists of about 2, 50,000 species of herbs, shrubs and trees. The angiosperms are divided into two classes: Dicotyledons and Monocotyledons
Examples: Grass, Bamboo, Coconut tree
General characteristics :
- The ovules are located within the ovary, so seeds are found enclosed within the fruit wall
- The male and female gametophytes which produce gametes are highly reduced.
- Male(pollen grains) and female(egg cells) gametes are aggregated in the flower.
- They show double fertilization
Difference between Gymnosperms and Angiosperms
Gymnosperms
1. In gymnosperms the reproductive structures are cones which are unisexual
2. The ovules are exposed, i.e., they are not located in the ovary.
3. After fertilization, the ovules develop into naked seeds.
4. The microspores and megaspores are produced by male and female cones
5. The pollen grains fall and germinate directly on the micropyle of the ovules
6. Fertilization is simple
7. Endosperm is haploid
8. In gymnosperms the pollination is by wind alone
9. In gymnosperms, generally the xylem contains only tracheids. Vessels are absent
10. The phloem has no companion cells
Angiosperms
1. In Angiosperms, the flowers are the reproductive organs and they may be both unisexual and bisexual.
2. The ovules are enclosed in the ovary.
3. After fertilization, the ovules develop into seeds inside the fruit.
4. The microspores are produced in anthers while the megaspores are produced in ovules of the ovary in flowers
5. The pollen grains fall on the stigma, germinate and the pollen tube carries the male gamete to the ovary
6. Fertilization is double
7. Endosperm is triploid
8. In angiosperms, different agents like wind, insects, bats etc are involved in pollination
9. Angiosperms vessels are always are present
