The Isoetopsida is a class of the Lycopodiophyta. All living plants belong to the genus Selaginella in the Selaginellales or to Isoetes in the order Isoetales. In the past, members of this group have sometimes been placed in the class Isoetopsida, sometimes in the Selaginellopsida or Lycopodiopsida. There are about 700 species of Selaginella and 140-150 species of Isoetes, with a cosmopolitan distribution but often scarce to rare. Some botanists split Isoetes, separating two South American species into the genus Stylites.[2]
The most famous group within the Isoetopsida is the "scale trees" (order Lepidodendrales), which include Lepidodendron. These massive trees flourished in marshlands of the Carboniferous. Quillworts are considered by some to be the last remnant of such fossil trees, with which they share some unusual features including the development of both wood and bark, a modified shoot system acting as roots, bipolar growth, and an upright stance.[3]
References
- ^ Cronquist, A.; A.H. Holmgren, N.H. Holmgren, & J.L. Reveal (1972). Intermountain Flora. 1. New York: Hafner. p. 177.
- ^ Jones, David L. (1987). Encyclopaedia of Ferns. Portland, Oregon: Timber Press. pp. 52-55. ISBN 0-88192-054-1.
- ^ Stewart, Wilson N.; Gar W. Rothwell (1993). Paleobotany and the Evolution of Plants (2nd ed.). Cambridge University Press. pp. 150-153. ISBN 0-521-38294-7.
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
