Question

In the mid-nineteenth century, paleobotanists investigating Carboniferous coal swamps observed that giant lycopsids such as Lepidodendron possessed an atypical secondary vascular architecture: unlike modern arborescent seed plants, whose trunks expand continuously through secondary xylem growth driven by a persistent vascular cambium, Lepidodendron derived its structural rigidity primarily from a thick, fibrous outer cortex (periderm) rather than an extensive central woody cylinder. Because the central vascular stele of these lycopsids remained slender relative to their immense height—often exceeding thirty meters—early structural morphologists inferred that the trees were mechanically unstable and restricted to saturated, low-energy depositional basins where dense canopy packing provided mutual physical support. However, recent biomechanical re-examinations incorporating finite-element stress modeling of periderm tissue suggest that the cortical cylinder achieved flexural rigidity comparable to modern hardwood xylem of equivalent diameter, albeit through a radically distinct stress-distribution mechanism. Furthermore, micro-tomographic analysis of preserved rooting structures (Stigmaria) demonstrates that lycopsid anchorage relied on an interconnected subterranean meshwork of lateral rootlets rather than deep taproots. This structural configuration allowed lycopsids to colonize unconsolidated, waterlogged substrates inaccessible to deep-rooting plants, though it exposed them to catastrophic uprooting during sudden hydrologic surges.

Consider each of the choices separately and select all that apply.

Based on the passage, which of the following can be inferred regarding Carboniferous lycopsids such as Lepidodendron?