Trimerophytina

Life reconstruction of Psilophyton, by Elfriede Abbe.

Belongs within: Tracheophyta.

The Trimerophytina are a group of vascular plants known from the Early (Pragian) to the lowermost Middle Devonian. They bore sporangia in pairs that are commonly preserved twisted around each other (Gerrienne 1997).

See also: Before the word for world was forest.

Characters (from Gerrienne 1997): Branching of axes complex but primarily dichotomous. Sporangia elongate, fusiform; borne terminally in pairs on main or lateral axes, commonly twisted around each other (possibly a standard part of their ontogeny); single longitudinal dehiscence line present, dehiscent sporangia opening into single C-shaped valve.

<==Trimerophytina [Trimerophytophyta, Trimerophytopsida]
    `--Trimerophytaceae G97
         |--Trimerophyton robustius G97
         `--Psilophyton Dawson 1859 G97
              |--P. burnotense G97
              |--P. charientos G97
              |--P. coniculum Trant & Gensel 1985 G97
              |--P. crenulatum G97
              |--P. dapsile Kasper et al. 1974 G97
              |--P. dawsonii Banks et al. 1975 G97
              |--P. forbesii Andrews et al. 1968 G97
              |--P. genseliae Gerrienne 1997 G97
              |--P. krauselii Obrhel 1959 G97
              |--P. microspinosum G97
              |--P. parvulum Gerrienne 1995 G97
              |--P. princeps G97
              `--P. szaferi Zdebska 1986 G97

Trimerophytina incertae sedis:
  Dawsonites G97
    |--D. arcuatus G97
    |--D. magnus G97
    |--D. roskiliensis Chaloner 1972 G97
    `--D. subarcuatus G97
  Hedeia Cookson 1935 G97
    `--H. corymbosa EE86
  Pertica G97
    |--P. dalhousii G97
    |--P. quadrifaria G97
    `--P. varia G97
  Gothanophyton Remy & Hass 1986 G97
  Tursuidea paniculata G97

*Type species of generic name indicated

REFERENCES

[EE86] Edwards, D., & D. S. Edwards. 1986. A reconsideration of the Rhyniophytina Banks. In: Spicer, R. A., & B. A. Thomas (eds)Systematic and Taxonomic Approaches in Palaeobotany.  Systematics Association Special Volume 31: 199–220. Clarendon Press: Oxford.

[G97] Gerrienne, P. 1997. The fossil plants from the Lower Devonian of Marchin (northern margin of Dinant Synclinorium, Belgium): V. Psilophyton genseliae sp. nov., with hypotheses on the origin of Trimerophytina. Review of Palaeobotany and Palynology 98: 303–324.