Nystroemiaceae

The Nystroemiaceae are Permian gymnosperms with ovulate structures showing some apparently ancestral features more typical of early seed plants, whereas the leaves and branches show derived character states of broad-leaved gymnosperms

Ecology & Form

Stems

  • Branches were probably woody with variability in its branching pattern

  • Long and short shoots were differentiated

Leaves

  • Vegetative leaf with a long petiole and a broad lamina with radiate reticulate venation

  • Lamina with entire or undulate margin and cordate or tapering base

Reproductive Structures

  • Frond-like ovuliferous organ

  • The main axis forking with pinnate lateral branches bearing numerous small bicornute ovules at their tips.

  • Leafy/ovuliferous complex arising from leaf axil

  • Ovuliferous organs attached in the axil of the petiole of leafy organ, or both organs crowded on a node

Classification

└Embryophytes

└Polysporangiophytes

└Tracheophytes

└Euphyllophyte

└Lignophytes

└Spermatophytes

└Nystroemiaceae †

Geologic Age

  • Middle - Late Permian

Nystroemia †

  • Halle 1929; Wang & Pfefferkorn 2010

  • Early - Late Permian of North China

  • Seed plant with multi-order branching system

  • Ovuliferous organ frond-like, with the main axis forking into two or more pinnate branches adaxially bearing numerous small bicornute ovules with zygomorphic symmetry

  • Vegetative leaf with a long petiole; lamina reniform, basally cordate or tapering, entire or slightly undulate at the margin; veins numerous, finely diverging and reticulate.

  • Leafy/ovuliferous complex arising from leaf axil, forming the last-order branches, which are alternative or opposite on the second-last-order axis

  • Ovuliferous organs attached in the axil of the petiole of leafy organ, or both organs crowded on a node.

N. reniformis

  • Wang et al. 2003

N. shouyangensis

  • Wang & Pfefferkorn 2010

  • Middle - Late Permian (Capitanian–Wuchiapingian) of Shouyang, Shanxi, China

  • Ovuliferous organ with the main axis forking into two or more pinnate-like branches adaxially bearing numerous small bicornute ovules with zygomorphic symmetry

  • Vegetative leaf with a long petiole; lamina reniform, basally cordate, entire or slightly undulate at the margin; veins numerous, finely diverging and reticulate

  • Leaves and ovuliferous organs attached to short shoots, forming the last-order branches


  • The most critical difference is that N. shouyangensis has leaves and ovuliferous organs arranged on a short shoot, whereas N. reniformis are arranged on a long shoot

  • The leaf laminae of N. shouyangensis have a very distinctly cordate base, whereas N. reniformis mostly have a wedge-shaped lamina base, although the lamina base of certain small leaves is cordate to a degree

  • The ovuliferous organs of N. shouyangensis as a rule appear as a main axis that distally bifurcates once, producing two subordinate pinnate branches bearing numerous small bicornute ovules, whereas N. reniformis are more irregular

Above: Nystroemia reniformis (From Fig. 4, Wang & Pfefferkorn 2010)

Above: Nystroemia shouyangensis (From Fig. 6, Wang & Pfefferkorn 2010)