Pertica †

Early Devonian plant with elaborate branching

Pertica is an extinct leafless trimerophyte, that was very tall for the time period in which it lived (Early Devonian). The plant had distinct nodes and internodes similar to horsetails. Pertica may be an intermediate taxon between early-branching forms (i.e. Psilophyton) and woody plants (lignophyte) plants, such as Tetraxylopteris

Named by Kasper and Andrews (1972) from compression fossils found in the Trout Valley Formation of northern Maine. In 1985, Pertica was named the state fossil of Maine.

Stems

This plant was strongly pseudomonopodial with a main upright stem and complex dichotomous branching in lateral axes.

  • Similar morphology to Psilophyton, but taller (1-3 m in height); probably largest plants on Early Devonian landscape

  • Primary axes have spiral branching such they appear quadriseriate (branches is four distinct rows)

    • Distinct internodes between secondary branches

    • Secondary branches emerging in pairs or near whorls

      • Subsequent branch orders may be dichotomous or pseudomonopodial

      • Branches covered in fine enations or hairs.

  • Anatomy: internal structure unknown due to compression

Leaves

  • No leaves

Reproductive Structures

  • Axes terminate in clusters of many elongate homosporous sporangia

Diversity