Pseudobornia †

Early horsetail ancestor

Ecology & Form

  • Vegetative features similar to Equisetales; Reproductive parts are similar to the Sphenophyllales

Stems

  • Distinct nodes and internodes

    • Basal nodes produce 1-2 first-order branches up to 3 m long

    • Second-order branches are opposite and decussate

    • Higher-order branches emerge in pseudo-distichous pattern

  • Pseudomonopodial or monopodial branching

    • 15-20 meters tall

  • Anatomy is unknown

Leaves

  • Originally called meiophylls

  • Produced only on high-order branches

  • Highly dissected leaflet attached to twice-dichotomous petiole

Roots

  • Underground portions unknown

Reproduction

  • Fertile branches up to 30 cm long

  • Each fertile unit exhibits whorled bracts and sporangiophores

    • Sporangiophores have upturned tips divided into two segments

    • Each sporangiophore has ~30 sporangia

Classification

Embryophytes

└Polysporangiophytes

└Tracheophytes

└Eutracheophytes

└Euphyllophytes

└Pteridophyta

└Equisetophytes

└Pseudoborniales †

Geologic Age

Diversity

  • Pseudobornia ursina † (Schweitzer 1967)