Pteridophytes exhibit diverse stem morphologies. Many species possess underground stems known as rhizomes, which facilitate vegetative propagation and survival. Additionally, many pteridophytes produce aerial stems that rise above the ground to support leaves and reproductive structures. Therefore, both rhizomatous and aerial stem types are characteristic features found within the group.

The sporophyte of Sphenopsida (such as Equisetum) is well-differentiated into a distinct root system, a jointed aerial stem, and small, scale-like leaves arranged in whorls at the nodes.

Leptosporangiate ferns are characterized by sporangia that develop from a single initial cell. This group is a major subclass within the class Pteropsida. Unlike eusporangiate ferns, leptosporangiate ferns typically have a thin sporangial wall and are the most diverse and common group of modern ferns found in various ecosystems today.

Most living pteridophytes are herbaceous and lack secondary growth, which is the process of increasing girth through the activity of the vascular cambium. While some extinct pteridophytes, such as the arborescent lycopsids, did exhibit secondary growth, the vast majority of extant species rely solely on primary growth for their development. This limitation restricts the overall size and longevity of most modern pteridophyte species.

In the genus Equisetum, the sporophyte exhibits a distinct node and internode structure. At each node of the secondary branches, small, scale-like leaves are arranged in a whorl. The number of leaves in these whorls is generally consistent with the number of ridges on the stem, typically ranging from 4 to 5 in many species, though this can vary by specific taxon.

Members of the class Lycopsida, such as Lycopodium and Selaginella, are vascular plants that possess a well-developed plant body differentiated into true roots, stems, and leaves. These organs are characteristic of the sporophyte generation in these pteridophytes, allowing for efficient transport of water and nutrients throughout the plant structure.

Psilotum is a genus of primitive vascular plants. In biological classification, the genus name is the first part of the binomial name. Therefore, Psilotum belongs to the genus Psilotum. It is often studied for its simple body structure, which lacks true roots and leaves, representing an early lineage of vascular plants within the division Pteridophyta.

A synangium is a specialized structure in certain pteridophytes where multiple sporangia are fused together. This collective arrangement is often found in various fern species and some primitive vascular plants. The fusion of sporangia into a synangium is an evolutionary adaptation that can provide structural support and protection for the developing spores before they are released into the environment.

The aerial parts of pteridophytes are covered by a waxy layer known as the cuticle. This layer is crucial for reducing water loss through transpiration, which is an essential adaptation for survival in terrestrial environments where water availability can be inconsistent.

The term 'Arthrophyta' (or Arthrophytes) is derived from the Greek words 'arthron' meaning joint and 'phyton' meaning plant. This name refers to the characteristic jointed appearance of the stems in members of the class Sphenopsida, such as Equisetum. The nodes are clearly defined, and the internodes are typically ribbed, giving the plant a segmented or articulated structure.