General account of Cycadofilicales
Cycadofilicales is an extinct order of seedless vascular plants that thrived during the Carboniferous period, approximately 360 to 299 million years ago. They are commonly referred to as the "cycad ferns" due to their fern-like foliage and their resemblance to modern cycads.
Cycadofilicales were an important group of plants during the Carboniferous, contributing to the lush tropical forests that covered large parts of the Earth at that time. They were among the earliest seed plants and played a significant role in the evolutionary history of plants.
These plants had a complex life cycle and exhibited characteristics of both ferns and cycads. They had a prominent sporophyte generation, which was the dominant phase of the life cycle. The sporophyte consisted of a tall stem with a crown of large, compound leaves. The leaves were pinnately divided, similar to those of ferns, but had a more cycad-like appearance.
The reproductive structures of Cycadofilicales were cone-like structures known as strobili. These strobili were borne at the top of the stem and produced spores. The spores were dispersed into the environment and gave rise to a gametophyte generation. The gametophytes were relatively small and inconspicuous, similar to those of ferns. They produced male and female reproductive cells that fused to form embryos, which developed into new sporophytes.
Cycadofilicales were characterized by their extensive root systems, which helped anchor them in the soil and absorb water and nutrients. They likely formed symbiotic relationships with mycorrhizal fungi, which aided in nutrient uptake. Some species of Cycadofilicales are known to have reached substantial heights, comparable to modern trees.
The decline of Cycadofilicales occurred by the end of the Carboniferous period, as they were outcompeted by other groups of seed plants, such as conifers and ferns. However, their evolutionary significance cannot be overstated. They represent an important transitional group between ferns and cycads, providing valuable insights into the development of seed plants.