Gymnosperms: Cycadopsida, Gnetopsida, Coniferopsida, and Pro-Gymnosperms

Some palaeozoic era fossils from the Devonian and Carboniferous periods were previously assumed to belong to Pteridophytes, but are now thought to be closer to gymnosperms, but not fully gymnosperms. Beck in 1960 identified linkages between two such fossils, archaeopteris fern-like fronds and callixylon gymnosperm-like trunks, these members were classed as the progymnospermopsida, a class of gymnosperms. Progymnosperms are thought to be the origin of both Cycadales and Coniferales by some Palaeobotanists. After the discovery of Rhynie flora and Pteridosperms, Stewart views the discovery of progymnospermopsida to be a watershed event that has improved our understanding of vascular plant evolution more than any other.

Gymnosperms: Definition, Characteristics, and Examples

The term Gymnosperm was first used by Scientist Theophrastus in his book ‘Enquiry into plants’. The word Gymno means nacked and Sperma means seed. Due to the presence of nacked seeds, they are also called Nacked seed-bearing plants. the Gymnosperms are called Phaenerogams with ovaries. Gymnosperms are woody plants that can range in size from enormous trees to little shrubs. Sequoia sempervirens is as tall as a 36 story building. Perhaps the smallest Gymnosperm is a Cycad, Zamia pygmea whose fronds are only 4 or 5 cm long. Sequoiadendron giganteum, on the other hand, is the largest and oldest.

Multiрle-сhоiсe questiоns (MСQs) аnd Рrасtiсe tests (Gymnosperms)

Question 1. Conifers have evolved to withstand harsh environmental conditions Because of A.Broad hardy leaves B. Superficial stomata C. Thick cuticle D. Presence of vessels Question 2. Coralloid roots are found in which of the following genera? A.Cycas B.Taxus C. Pinus D. Sequoia Question 3. Vessels are absent in the wood of A.Pine B. Eucalyptus …

Multiрle-сhоiсe questiоns (MСQs) аnd Рrасtiсe tests (Gymnosperms) Read More »