Vegetative and reproductive morphology of Othniophyton elongatum (MacGinitie) gen. et comb. nov., an extinct angiosperm of possible caryophyllalean affinity from the Eocene of Colorado and Utah, USA
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View abstract on PubMed
Summary
This summary is machine-generated.Fossil Eocene angiosperm Othniophyton elongatum, previously classified as Oreopanax, exhibits unique features necessitating a new classification. This ancient plant does not fit modern plant families, highlighting the diversity of ancient vegetation.
Area Of Science
- Paleobotany
- Angiosperm Evolution
- Fossil Flora Analysis
Background
- Eocene foliage previously assigned to Oreopanax (Araliaceae) was re-examined.
- Attached reproductive structures (inflorescences, infructescences) were found to be inconsistent with Araliaceae characteristics.
Purpose Of The Study
- To reassess the taxonomic affinities of a fossil angiosperm using detailed morphological characters.
- To investigate phyllotaxy, bud morphology, infructescences, and seed anatomy.
Main Methods
- Study of fossil impression remains from the Green River Formation (ca. 47 Ma).
- Utilized low-angle reflected light and optical shadow effect microscopy.
- Detailed analysis of vegetative and floral buds, stamens, fruits, and seeds.
Main Results
- The fossil, Othniophyton elongatum gen. et comb. nov., possesses distinct leaf venation, inflorescence, flower, fruit, and seed structures.
- Characters include simple leaves, axillary cymes, actinomorphic bisexual flowers, persistent stamens, superior ovary, and berries with ridged seeds.
- These features collectively refute placement in Araliaceae and most extant angiosperm clades.
Conclusions
- The unique combination of traits does not align with any extant plant family.
- The fossil shows some similarities to the order Caryophyllales but retains key differences.
- This discovery underscores the presence of unclassifiable taxa in Eocene vegetation.
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