Wikipedia
Serrulacaulis
Serrulacaulis was a genus of Silu-Devonian land plant with branching axes.
A cladogram published in 2004 by Crane et al. places Serrulacaulis in the core of a paraphyletic stem group of broadly defined " zosterophylls", basal to the lycopsids (living and extinct clubmosses and relatives).