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Bennettitales

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gohil sanjay bhagvanji

This document summarizes the Bennettitales, a group of fossil plants that flourished during the Mesozoic era. It describes two families of Bennettitales: Bennettitaceae and Williamsoniaceae. Bennettitaceae had deeply sunk flowers on short, thick trunks, while Williamsoniaceae had fully exposed flowers on slender stems. The document provides details on the anatomy, reproduction, and classification of these two extinct families of seed plants.

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Bennettitales Presented by : Patel Vanita l M.sc Sem : 1 CBO: 402
Contents • What is Bennettitales ? •Classification •Bennettitaceae family •Williamsoniaceae family
What is Bennettitales ? • This group of fossil plants flourished well during the Triassic to lower Cretaceous periods of Mesozoic era. • As the Carboniferous period is called the "Ages of ferns " the Mesozoic era is called the "Ages of cycads. "
History • The name " Bennettitales " has been given to honor J. J Bennett an English botanist. • The fossilized trunks of genus Bucklandia was the first specimen of Bennettitales collected from Great Britain in 1825.
Classification • Walton ( 1940 ) recognized following two families in Bennettitales. 1. Bennettitaceae 2. Williamsoniaceae
1. Bennettiteae : Flower deeply sunk among the persistent leaf bases and were present on short thick trunks. Example : Cycadeoidea 2 . Willamsonieae : flower fully exposed and present on slender stems. Example : williamsoniella
Bennettitaceae Anatomy : • The unique trunks have been nicely illustrated by wieland in his book 'American fossils Cyads ' and by ward in his book 'status of the Mesozoic flora. '
Bennettitales
Microsporophyll or Androecium • The tip the microsporophyll was fused to its base. • The distal part of each microsporophyll was parenchymatous with no indications of fusion or canals. • Each pollen capsule or synangium measures 3.5 *2.5 millimeters and contained a varying number of pollen sacs or micro sporangia.
• The number is stated to very between 20 to 30 per synangium and are separated by distinct walls. • The synangium has a several layered thick wall. • The outer layer is composed of palisade like cells that have thick walls.
Gynoceium • The young nucleolus is made up of thin walled cells those at the chalazal and being much smaller than those at the microsporpylar end. • The cells in the micropylar region are much elongated and are up to 80 u long. • A single cells with a pointed tip appears development. • The cells at the chalazal end are smaller.
Bennettitales
Bennettitales
Williamsoniaceae Anatomy : • The primary vasculature consisted of a ring of endarch conjoint and collateral vascular bundles. • The pith extended between the vascular bundles in the from of pith rays. • The secondary wood formed an extensive cylinder around the primary xylem .
Reproduction Female flower : • The tip of the receptacle was naked. • The ovule had short stalks that bear the body of the ovule which consisted of a single integument surrounding the nucleolus. • The nucleolus had a prominent beak and a pollen chamber.
Bennettitales
Male flower : • The pinnae were almost opposite and slightly tapered out wards. • The proximal petiole like portion bore numerous globose pollen containing bodies. • These leaf like bodies contained Syndetocheilic stomata that are characteristic of Bennettitales.
Bennettitales
Reference Botany for degree students Gymnosperms by - P.C.VASISHTA - A.K.SINHA - ANIL KUMAR  https://en.m.Wikipedia.org
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Bennettitales

  • 1. Bennettitales Presented by : Patel Vanita l M.sc Sem : 1 CBO: 402
  • 2. Contents • What is Bennettitales ? •Classification •Bennettitaceae family •Williamsoniaceae family
  • 3. What is Bennettitales ? • This group of fossil plants flourished well during the Triassic to lower Cretaceous periods of Mesozoic era. • As the Carboniferous period is called the "Ages of ferns " the Mesozoic era is called the "Ages of cycads. "
  • 4. History • The name " Bennettitales " has been given to honor J. J Bennett an English botanist. • The fossilized trunks of genus Bucklandia was the first specimen of Bennettitales collected from Great Britain in 1825.
  • 5. Classification • Walton ( 1940 ) recognized following two families in Bennettitales. 1. Bennettitaceae 2. Williamsoniaceae
  • 6. 1. Bennettiteae : Flower deeply sunk among the persistent leaf bases and were present on short thick trunks. Example : Cycadeoidea 2 . Willamsonieae : flower fully exposed and present on slender stems. Example : williamsoniella
  • 7. Bennettitaceae Anatomy : • The unique trunks have been nicely illustrated by wieland in his book 'American fossils Cyads ' and by ward in his book 'status of the Mesozoic flora. '
  • 9. Microsporophyll or Androecium • The tip the microsporophyll was fused to its base. • The distal part of each microsporophyll was parenchymatous with no indications of fusion or canals. • Each pollen capsule or synangium measures 3.5 *2.5 millimeters and contained a varying number of pollen sacs or micro sporangia.
  • 10. • The number is stated to very between 20 to 30 per synangium and are separated by distinct walls. • The synangium has a several layered thick wall. • The outer layer is composed of palisade like cells that have thick walls.
  • 11. Gynoceium • The young nucleolus is made up of thin walled cells those at the chalazal and being much smaller than those at the microsporpylar end. • The cells in the micropylar region are much elongated and are up to 80 u long. • A single cells with a pointed tip appears development. • The cells at the chalazal end are smaller.
  • 14. Williamsoniaceae Anatomy : • The primary vasculature consisted of a ring of endarch conjoint and collateral vascular bundles. • The pith extended between the vascular bundles in the from of pith rays. • The secondary wood formed an extensive cylinder around the primary xylem .
  • 15. Reproduction Female flower : • The tip of the receptacle was naked. • The ovule had short stalks that bear the body of the ovule which consisted of a single integument surrounding the nucleolus. • The nucleolus had a prominent beak and a pollen chamber.
  • 17. Male flower : • The pinnae were almost opposite and slightly tapered out wards. • The proximal petiole like portion bore numerous globose pollen containing bodies. • These leaf like bodies contained Syndetocheilic stomata that are characteristic of Bennettitales.
  • 19. Reference Botany for degree students Gymnosperms by - P.C.VASISHTA - A.K.SINHA - ANIL KUMAR  https://en.m.Wikipedia.org