Sphenophyllales

Sphenophyllales

 

an order of fossil plants with jointed stems. They apparently were lianas that required support; this is indicated by their long but extremely slender ligneous stems and the presence of spines in some types. The number of cunéate leaves on each whorl were in multiples of three (from six to 12). Sphenophyllales appeared in the late Devonian period and gradually died out in the late Permian and early Triassic periods.


Sphenophyllales

 

an order (or class) of extinct plants with jointed stems. They differ from other plants with jointed stems by the absence of a medullary cavity in the long and slender lignified stem and by the presence of leaf blades with fan-shaped venation. The sporangia are gathered into homosporous and heterosporous strobiles of diverse structure. Sphenophyllales are most characteristic of tropical flora.