Triassic Period

Biological

Flora

• Corystosperms, cycads, bennettitaleans, and ginkgophytes increase in number 

• Glossopterids become a conspicuous part of flora until the late Early Triassic (Anisian-Olenekian)

• Peltasperms disappear during the Late Triassic

• Lycophytes

  • Representatives from the Lycopodiales, Selaginellales, and Isoetales survive but are less prominent

  • Pleuromeiales, close relatives of the Lepidodendrids appear during the Triassic and disappear at the end Triassic

• Equisetophytes & Ferns

  • Sphenophyllales disappear at the end of the Early Triassic, but horsetails continue as riverside flora in many areas.

  • One of the oldest surviving genera, Equisetum, appears during the Triassic.

• Angiosperms?

  • Pre-Cretaceous angiosperm evidence is controversial, and possible evidence exists only as microfossils (i.e. pollen)

  • The affinity of the pollen group described as Crinopolles (including the genera Tricrinopollis, Monocrinopollis, Dicrinopollis, and Zonacrinopollis) from the Late Triassic (Carnian) of Virginia (Cornet 1989) continues to be a subject of controversy (e.g., Zavada 2007; Friis et al. 2011; Doyle 2012).

  • These pollen grains show some clear angiospermous features (Cornet 1989b); they are monosulcate and have a semitectate (reticulate) outerwall, which is connected by columellae to the inner wall (nexine). Other features, like the uniformly-thickened exine, are more gymnosperm-like (Doyle and Hotton 1991). 

  • Recently, it has been suggested that the Crinopolles group may represent plants on the angiosperm stem lineage (Doyle and Hotton 1991; Doyle and Donoghue 1993; Doyle 2012).