What is Williamsonia in botany?
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.
Who discovered Williamsonia Sewardiana?
It has been reported from Upper Triassic period but was more abundant in Jurassic. This was earlier discovered under the name Zamia gigas by Williamson (1870) but has now been named as Williamsonia. Professor Birbal Sahni (1932) described W. sewardiana from Rajmahal Hills of Bihar (India).
What do you mean by Glossopteris?
Glossopteris, genus of fossilized woody plants known from rocks that have been dated to the Permian and Triassic periods (roughly 300 to 200 million years ago), deposited on the southern supercontinent of Gondwana. Glossopteris occurred in a variety of growth forms.
What did Glossopteris look like?
Glossopteris occurred in a variety of growth forms. Its most common fossil is that of a tongue-shaped leaf with prominent midrib and reticulate venation. Glossopteris leaves are commonly found in thick mats, and thus some authorities speculate that the plants were deciduous.
Why did Glossopteris go extinct?
Glossopteris was part of a primitive gymnosperm order called Glossopteridales and flourished during the Permian and Triassic periods, roughly 200-300 million years ago. This species eventually perished due to extensive volcanic activity in Siberia, causing massive global extinction.
Is Glossopteris a fossil?
Glossopteris fossils are found on all of the southern continents. They have been found in Australia, South America, Africa, India, and Antarctica. Because the fossil leaves are found in thick mats scientists think that glossopteris were deciduous plants.
Why did Glossopteris become extinct?
What did the Glossopteris look like?
What kind of plant was Glossopteris?
seed ferns
Glossopteris [etymology: from Ancient Greek γλῶσσα (glôssa, ” tongue “) + πτερίς (pterís, ” fern “)] is the largest and best-known genus of the extinct Permian order of seed ferns known as Glossopteridales (also known as Arberiales, Ottokariales, or Dictyopteridiales).
What does the Glossopteris fossils tell us?
The glossopteris fossils reflects the evidence of separation of continents like southern Africa, Australia, India and Antarctica which was largely separated by huge and wide ocean which was larlier connected with each other.
Why is the Glossopteris important?
They literally reveal how the world we recognise today took shape. Glossopteris was easy to recognise because of its distinctive leaves; the name means “tongue-fern” in Greek, because of its shape. Fossil evidence suggests that the plants probably grew in diverse habitats and came in different forms.
What do the Glossopteris fossils tell us Brainly?
What is Williamsonia?
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.
Is this the first reproductive structure of Williamsoniaceae from North America?
An anatomically preserved cone of Williamsonia has been discovered in Campanian rocks of Vancouver Island. This was the first reproductive structure of Williamsoniaceae to be recovered from western North America.
What are the characteristics of the stamens of Williamsonia?
The stamens of Williamsonia curved inward and upward. Williamsonia produced ovulate sporophylls up to 4 inches (10 cm) in length. Its stalked seeds would have grown from a central receptacle, and the entire cone of Williamsonia would have been surrounded by protective bracts (which are often the only part of the plant to undergo fossilization).
How does Williamsonia sewardiana Sahni differ from Cycadeoidea and cycads?
The group differs both from Cycadeoidea and cycads in some important features, in the stem anatomy and also in the form and structure of fructification. An Indian type Williamsonia sewardiana Sahni has been described from the Jurrasic period. It was found in a silicified condition in Rajmahal Hills (Bihar) which is made up of upper Gondwana rocks.