Vladimariales

Ginkgo-like gymnosperm

The Vladimariales were a Mesozoic group that may be closely related to the ginkgophytes. Vladimaria had a collar underneath its seeds, which is reminiscent of Ginkgo

Ecology & Form

Stems

  • Unknown, except for stalks of capsules

Leaves

  • Unknown

Roots

  • Unknown

Reproduction

  • Plants with peltate, radially symmetrical seedbearing organs

    • Tese are composite capsules, formed by fusion of several closed elementary capsules, which are arranged in a whorl on thin axis and inverted relative to it and base of composite capsule.

  • Composite capsule dehisced on several lobes along line of fusion of elementary capsules

  • Each capsule contained solitary seed

  • Seeds, sitting on short stalks, inverted relative to composite capsule axis

  • Seeds fusiform, slightly curved, with chalaza slightly asymmetrical and weakly concave in place of stalk attachment; micropile very long, with apex fused to margins of small opening in distal margin of capsule.

  • Nucellus fused with integument more than on two thirds, megaspore membrane absent

  • Axis base of composite capsule sustained by collar on thick stalk, protecting micropilar tips of seeds

  • Stalk with several radially arranged collateral vascular bundles

  • Their quantity corresponds to quantity of elementary capsules, form ing composite capsule

  • Metaxylem tracheids in vascular bundles with scalariform bordered pits

  • Extensive resin canals and cavities presented in cortex of stalk, collar, and composite capsule

  • Outer epidermis of composite capsule strongly cutinized, bearing numerous perigenous mono or polycyclic stomatal apparatuses, without sutures, despite of area sustained by collar, where radially arranged sutures distinctly expressed on cuticle

  • Sutures mark lines of fusion of capsules

  • Stalk, bearing collar, upper surface of collar near its axial part, composite capsule axis, and all area of composite capsule sustained by collar, papillose; other surface of composite capsule without papillae

Geologic Age

Classification

Embryophytes

Polysporangiophytes

Tracheophytes

Euphyllophytes

Lignophytes

Spermatophytes

Ginkgoopsida

Vladimariales

Diversity

Vladimaria octopartita