The appendages, or phylloids, were considered to be enations, comparable to the leaves of Lycopodium.
They are of two kinds, fertile, composed of a vascularized stalk and its terminal sporangium, and vegetative, or sterile, termed "phylloids " (this word is used in a different sense from that of Lignier who applied it to enations, or emergences).
The view that lycopod leaves are enations, instead of being telomic in origin, is also accepted by Takhtajan (1953).
Therefore, the vegetative organs of the psilotophytes are interpreted to be homologous to the systems of axes and enations
that also characterize extinct trimerophytes.