Shared body plans of lycophytes inferred from root formation of Lycopodium clavatum

Late Silurian to early Devonian lycophytes had prostrate aerial axes, while subordinate organs or subterranean axes were formed around the dichotomies of axes. The are hypothesized have evolved into root-bearing (rhizophores) and roots in extant Selaginellaceae Lycopodiaceae, respectively. Consistent with this hypothesis, rhizophores on shoots Selaginellaceae. However, it has remained unclear whether borne same position Lycopodiaceae. In addition, form endogenously stem, but no data available regarding tissues stem from which they arise. study, we tracked root development clubmoss, Lycopodium clavatum , based anatomical sections 3D reconstructed images. vascular tissue is encircled by ground meristem, supplies cortical cells outwardly periclinal divisions. A linear parenchymatous present ventral side cylinder, call “ventral tissue” study. We found that primordia possibly tissue. always initiate at positions close stem. root-initiating supports suggestion share a body plan ancestry.