1. Describe in brief the general characters of Gymnosperms.
2. Describe the external morphology of Williamsonia.
3. Describe the anatomical structure of Rhynia with the help of suitable diagram.
4. What is periderm? Describe briefly the development of periderm in angiosperm.
5. Mention the difference between dicot and monocot stem.
6. Write short notes on (any one)
a). Histogen Theory
b). Intrastellar secondary growth.
Answers
1 ]Definition of Gymnosperms:
One crucial step in the evolutionary history of all plants was the development of seeds. Seeds provide a viable means for dispersal of offspring without the need for water. They're a far more efficient way of dispersal and allow plants to exist away from direct sources of water.
Characteristics of Gymnosperms
Gymnosperms are a group of plants with the following unique characteristics:
They do not have an outer covering or shell around their seeds
They do not produce flowers
They do not produce fruits
They are pollinated by the wind
2].Williamsonia is an extinct genus of plant belonging to Bennettitales, an order of seed plants which bore a resemblance to cycads. Fossilized specimens of Williamsonia have been discovered worldwide.
3].