Pentoxylales

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Pentoxylales
Temporal range: Jurassic–Early Cretaceous
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Spermatophytes
Order: †Pentoxylales
Pilger and Melchior, 1954
Genera
Synonyms

Pentoxyleae Sahni, 1948

Pentoxylales is an extinct order of seed plants known from the Jurassic and Early Cretaceous of East Gondwana.

Discovery

The first specimens belonging to Pentoxylales were reported by Birbal Sahni in 1948 from Jurassic-Cretaceous strata of the Rajmahal Hills of northeastern India. Remains have subsequently been reported from New Zealand, Australia and Antarctica.[1] The oldest records of the group date to the Upper Jurassic, though there are unconfirmed Early Jurassic records.[2]

Morphology

Stem

The stem of Pentoxylales, referred to by the

Pentoxylon, consists of 5 or 6 wedge shaped segments embedded within thin walled ground tissue.[1]

Leaves

Leaves of Pentoxylales are of the strap shaped

midrib.[1]

Pollen organs

The pollen organs of Pentoxylales, referred to the morphogenus Sahnia, consist of

monosulcate and approximately 25 µm long.[1]

Seed bearing organs

Seed bearing organs of Pentoxylales, dubbed

seed cones, seed-bearing fruits, or female flowers. The seeds are apparently sessile.[1]

Whole plant reconstruction

The

brambles.[3]

Phylogenetics

The affinities of Pentoxylales remain obscure, phylogenetic analyses have proposed various affinities with other seed plants groups, including glossopterids and Bennettitales, but evidence for this is inconclusive, and they cannot be definitively linked with any other seed plant group.[1]

References

  1. ^
    ISBN 978-0-12-373972-8
    , retrieved 2021-03-17
  2. ^ Pattemore, G.A., Rigby, J.F. and Playford, G., 2015. Triassic-Jurassic pteridosperms of Australasia: speciation, diversity and decline. Boletín Geológico y Minero, 126 (4): 689-722
  3. ^ Howe, J., & Cantrill, D. J. (2001). Palaeoecology and taxonomy of Pentoxylales from the Albian of Antarctica. Cretaceous Research, 22, 779–793.
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