Fruiting Body of Dicroidium Seed Fern Fossil

Umkomasia sp

Geological Time: Triassic

Size: 11 mm by 9 mm on a 38 mm X 50 mm matrix

Fossil Site: Merrywood Coal Mine, Royal Gorge, Tasmania, Australia

Dicroidium fossilCorystosperms or fork-leafed seed ferns are a group of extinct plants with mostly fern-like foliage but with real seeds found in the Southern Hemisphere lands of Gondwana. The flora of Gondwana evolved in isolation from the rest of Pangaea because of an arid desert that persisted near the equator. The seed fern Dicroidium, like Glossopteris, occurred across Gondwana, and thier fossils contributed to developing the theory of Continental Drift. They possessed elaborate reproductive structures which had their known nomenclature. The female reproductive structures were of the Umkomasia type, while the male pollen-bearing structures were termed Pteruchus. They serve as important index fossils, and some data indicates that they may have persisted into the Cretaceous when the angiosperms first appeared. Triassic plants are fairly rare in the fossil record.

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