gymnosperm, Glossopteridales, Glossopteris

Order of Gymnosperm Glossopteridales, Genus Glossopteris, Morphology, ANATOMY,Reproductive biology

1. Glossopteridales Submitted To: Dr.Antra Chatterjee Dr. Harmanjit kaur Dr.Geeta Devi Submitted By: Jagriti Dubey

2. Glossopteridales and Glossopteris Glossopteridales included an extinct group of seed plants (Gymnosperms). They were originated during the Permian. period on the Gondwana Continent. They became the dominant vegetation in the Permian period. Glossopteris-Leaf shape

3. They extinct completely by the end of the Triassic period. The order name derived from the genus Glossopteris. Glossopteris is the best-known member of Glossopteridales. Glossopteris is a leaf. The name 'Glossopteris' means 'tongue-fern. '. Glossopteris-”Tongue Shaped Leaf”

4. The name was used to describe fossil leaves from India and Australia that were spatulate and tongue-shaped (Glossa= tongue) About 70 species of Glossopteris have been recognized from India alone. Glossopteris was also reported from South America, Australia, Africa, and Antarctica.

5. Morphology and Anatomy A small to medium-sized highly branched tree Leaves were dorsiventral Leaf lamina was flat in the dorsal side. Venations were reticulate Veins were parallel but anastomosing. Lateral veins originated from the midrib Midribs were with tracheids of scalariform or pitted thickening.

6. In the ventral side of the leaf, the midrib and veins were raised Mesophyll was differentiated into palisade and spongy tissues. Stomata were present on the lower surface of the leaf. The stomata were haplocheilic type Stomata present between the veins. Stomata were sunken type, indicate xerophytic adaptation. Stomatal subsidiary cells were papillate.

7. Important Genera of Glossopteridales Leaves: Glossopteris, Gangamopteris Stem and Root: Vertebraria Male Fructification: Glossotheca Vertebraria-stem of Glossopteridales

8. Male Fructification Reproductive B iology Male Fructification: Glossotheca Female Fructifications Two types: (1). Cupular fructifications: Pterigospermum (2). Multi-ovulate fructifications: Scutum

9. Multi-ovulate Frutification Leaf edges rolled over to form an enclosing structure to protect the seeds.

10. Fructifications of the Glossopteridales poorly preserved in fossils. Reproductive structures were unusual as the foliage leaves. Reproductive structures were born on the leaves as in "Pteridospermales Pollen and seeds were produced on separate leaves. This indicates unisexual strobilus. Pollen grains were produced inside the sporangia Seeds were produced on the under surface of the leaves.

11. Sporangia were formed on modified leaves called sporophylls. Each sporangium bear staked pollen sacks. Ovulate bearing organs are more preserved in fossil than pollen. Female strictures were very diverse indicating a wide diversity among this group.

12. Hairs or trichomes may be present on the leaves. The hairs may be branched or unbranched