Glossopteris

Glossopteris:-

Systematic Position:-

Kingdom:- Plantae

Division:- Gymnospermae

Order:- Glossopteridales

Family:- Glossopteridaceae

Genus:- Glossopteris

Structure:-

1. Roots of Glossop­teris:-

> The detached roots of Glossopteris plant are called Vertebraria. 

> The roots are flattened and grooved with wedge-like sec­tors that radiate from the centre of the axis.

> The wedges are made up of secondary xylem which covers the central polyarch protoxylem. 

> The pycnoxylic secondary xylem strands alternate with protoxylem strands. 

> In young stage, the cavities that formed between the radiating arms suggest that the plant grew in semiaquatic environment.

2. Leaves of Glossop­teris:-

> Glossopteris leaves are simple, entire and sessile (rarely petiolate, e.g., G. petiolata). 

> Leaves show a great variation in size and shape (linear lanceolate to spathulate ovate). 

> They have a strong midrib from which numerous longitudinally running veins pass out to form a reticulate pattern or remain free.

> Leaf anatomy shows a typical dorsiventral and hypostomatic nature with irregularly dispersed haplocheilic, sunken stomata. 

> Some species show a- hypodermal layer. 

> Mesophyll is differentiated into palisade and spongy parenchyma. Some scale leaves (rounded or lanceolate) are found to be associated with Glossopteris leaves.

> Some other less common leaf genera name­ly, Gangamopteris, Palaeovittaria, Rubidgea, Euryphyllum, Rhabdotaenia are also included under Glossopteridaceae family due to their identical form, venation pattern and cuticular structure.

> Gangamopteris (Lower Permian) leaf is identical to Glossopteris except the absence of well.-defined midrib. 

> Rhabdotaenia is distinguished from other leaf genera due to the presence of non-anastomosing lateral veins.