Order Psilophytales is a group of extinct plants that first appeared in the Devonian period. The order is characterized by slender branching stems with no leaves, and simple spore-producing structures called sporangia. While there are no exact synonyms for the term "Order Psilophytales," some related terms could include "whisk ferns," "naked seed ferns," or simply "psilophytes." These terms all refer to the same general group of plants, and are commonly used in scientific literature and discussions. Understanding the relationships between different groups of plants is an important part of studying biology, and the Order Psilophytales serves as an important example of early land plant evolution.