General Characters of Bennettitales
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’. It is due to the fact that Cycadeoideales co-existed with Cycadales during Mesozoic era from Jurassic up to Cretaceous period, and hence this period is called Age of Cycads.
> Bennettitales are found either in the form of compressions or petrifactions. Due to Cycad-like form of their fronds and the presence of short stems covered with an armour of presistent leaf bases Bennettitales (Cycadeoideales) have been treated under Cycadophyta by some workers. However, the two groups are quite distinct from each other and maintain their independent identity.
General Characters:-
1. These extinct Mesozoic plants were present were present on the earth from Triassic to Cretaceous.
2. Bennettitales were so abundant during Mesozoic era that this period is known as ‘Age of Cycads’.
3. The members of this group are found either as compressions or petrifactions.
4. The stems were stout or slender and had a wide pith.
5. The stem grew very slowly and had manoxylic wood.
6. Resembling living Cycads, the Bennettitalean leaves were mostly pinnately compound, and only occasionally simple.
7. Venation was open, and only rarely closed.
8. Syndetocheilic type of stomata were present.
9. The wall of the epidermal cells was sinuous.
10. The reproductive organs were organised in the form of hermaphrodite (e.g. Cycadeoidea) or unisexual (e.g. Wielandiella) “flowers”, which in turn were protected by many bracts.
11. The ‘flowers’ developed in the axil of leaves.
12. Male reproductive organs were borne in a whorl. They were free or fused, entire or pinnately compound.
13. Microsporangia were present abaxially in the form of synangia.
14. Microsporophyll’s sometimes surrounded megasporophylls forming hermaphrodite “flowers”.
15. Ovules were numerous and stalked and borne on a conical, cylindrical or dome-shaped receptacle.
16. Many inter-seminal bracts were present on the ovule containing receptacle.
17. The scales or bracts were united at end to form shield through which micropyle protrudes.
18. Seeds were dicotyledonous.