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New specimens of Schmeissneria, S. sinensis Wang sp. nov., are reported from …


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Biology Articles » Paleobiology » Paleobotany » Schmeissneria: A missing link to angiosperms? » Tables

Tables
- Schmeissneria: A missing link to angiosperms?

Table 1

Comparison of Schmeissneria to Ginkgoales, Gnetales, and angiosperms.
Characters Schmeissneria [24,*] Ginkgoales[24,31,32,45] Gnetales[31-32,47,83-84] Angiosperms[1]
Long/short shoot + + - +/-
Shoot articulate - - + +/-
Phyllotaxis Irregular spiral Spiral on short shoot Opposite/whorled Opposite, whorled, spiral
Leaf Slender-cuneiform, obtuse apex Fan-shaped, or cuneiform Strap-like, triangular, linear or oval-shaped Various
Venation Parallel Dichotomous Parallel or reticulate Various
Unisexuality + + + (-) +/-
Reproductive axis articulate - - + +/-
Bract - - + +/- (?)
Bract arrangement N/A -(? bract scale seed complex) Whorled/paired Whorled, paired, or N/A
Ovuliferous unit position On peduncle tip, in pair On peduncle tip, single, pair or more in group In bract axil, one to many in a group Terminal/axillary
Ovuliferous unit with septum + - - +/-
Ovule Completely enclosed by central unit wall Exposed through micropyle Exposed through micropylar tube Completely enclosed by carpel or secretion
Micropylar tube - - + -

Note that the character of enclosed ovule distinguishes Schmeissneria and angiosperms from the other two groups.*: information from this paper.

Wang et al. BMC Evolutionary Biology 2007 7:14   doi:10.1186/1471-2148-7-14

Table 2

Comparison between Schmeissneria and other possibly related fossil taxa.
Appendage arrangement Appendage shape No. appendages per peduncle Appendage opening orientation Appendage apex Seed/central unit position Ovule completely enclosed Vertical septum No. ovules/seeds per cupule/central unit Peduncle connects to
Schmeissneria(young) [24,*] Irregular Globose, in pair 2 Away from axis More or less extended Within the sheathing envelope + + 2? Envelope
Schmeissneria(mature)[24] Irregular Sickle-like, single 1–2 Away from axis Wing-shaped Below the wing, enclosed (?) ? ? 1? Seed?
Ktalenia[75] Opposite, subopposite Globose 1 Down More or less extended Within cupule - - 1–2 Cupule
Schizolepis[73] Spiral Bilobate 1 Up Lobate Axil of scale - - 2 Scale
Drepanolepis[74] Spiral Sickle-like 1 Up Wing-shaped Axil of scale - - 1 Scale
Leptostrobus[44,76] Spiral Round bivalvate 1 (2 valves) Away from axis Round, thickened margin Within capsule, axil of valves - - Several Cupule
Caytonia[33,58] Opposite Globose 1 To axis Extended lip Within capsule - - Several Cupule
Karkenia[24,77-78] Irregular Round-oval 1 To axis Acuminate apex On peduncle - - 1 Ovule/seed

Note the characters (enclosed ovule, vertical septum) distinguishing Schmeissneria from the others. *: information from this paper.

Wang et al. BMC Evolutionary Biology 2007 7:14   doi:10.1186/1471-2148-7-14

 


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