Asselian Age

What happened during this time?

Biological

Flora, spore-bearing

• Forests of scale trees, ferns, horsetails, progymnosperms, and seed ferns found in Chinese localities

• The dominant trees are noeggerathian progymnosperms with an emergent layer of scale trees, such as Sigillaria in some areas

• There are abundant marattialean tree ferns, as well as smaller zygopterid ferns

• Sphenophyllophytes are found in the under-story and horsetails along rivers and wetlands

• The earliest known true fern,Oligosporangiopteris zhongxiangii, has been found from the Inner Mongolia, North China (Frojdová et al. 2021)

Flora, seed-bearing

• The Cordaitales diversify in Euramerica, and Glossopteridales diversify in Gondwana

• Seed ferns, such as the Medullosales, Callistophytales, and Peltasperms were still on the landscape surviving from the Carboniferous

  • Medullosids had a  (semi-)self-supporting growth habit with a high water-conducting potential of these plants, thriving under seasonally-dry climate on wet, rocky soils showing proximity to the groundwater level (Luthardt et al. 2021)

• Giganopterids, complex seed ferns, were among the most striking and important plants of the Cathaysian flora of Sino-Malaya (Wang 1999)

• The earliest record of ginkgophytes, Trichopitys, occurs during this time (Zhou 2009)