Sporne (1965) discussed Palaeocycas as the only fossil genus belonging to Cycadaceae. Florin (1933) described the female sporangiophores of this genus belonging to Palaeocycas integer and its leaves belonging to Bjuvia simplex. The female sporangiophores of Palaeocycas integer were described from Upper Triassic rocks of Sweden. These sporangiophores are believed to have borne seeds. Its leaves resembled that of present [...]
In this article we will discuss about Pentoxylales. After reading this article you will learn about: 1. Systematic Position of Pentoxylales 2. Discovery of Pentoxylales 3. Distinguishing Features 4. Stem Genera 5. Leaves 6. Seed-Bearing Organ 7. Affinities 8. Conclusion. Contents: Systematic Position of Pentoxylales Discovery of Pentoxylales Distinguishing Features of Pentoxylales Stem Genera of Pentoxylales Leaves of Pentoxylales Seed-Bearing [...]
The following points highlight the three main steps involved in embryogency in cycas. The steps are: 1. Development of Zygote 2. Structure of Seed 3. Germination of Seed. Embryogency in Cycas: Step # 1. Development of Zygote: The diploid osspore or zygote is the first cell of the sporophyte. It contains dense cytoplasm and a large nucleus. The nucleus moves [...]