Moniliformopses

From Palaeos

Chlorobionta
  |--Chlorophyta
  `--Charophyta
       `--Embryophyta
            |--Marchantiophyta
            |--Bryophyta
            |--Anthocerotophyta
            `--Tracheophyta
                 |--Lycopodiopsida
                 `--o--o--Equisetopsida
                    |  `--Pteridopsida
                    `--Spermatophytata

[edit] Introduction and Description

The Moniliformopses are the horsetails and ferns, including the Psilotidae (whisk ferns). They are closely related to the seed plants. Pryer et al. (2001). So, for example, they exhibit apical growth (meristem) in both sporophyte and gametophyte generations. They have well-developed roots, megaphyllous leaves and the vascular system needed to make use of both. However, both may have been evolved independently of higher plants. Friedman et al. (2004). In addition, Moniliformopses lack a complete vascular cambium, and growth of xylem is restricted to lobes of the primary xylem strand.

Since this is a new clade -- discovered, for all practical purposes, by Preyer's group, we have little to say about Moniliformopses as a taxon, and defer discussion to a fuller consideration of its three component parts. The Psilotidae are the most basal, followed by the horsetails, then the remainder of the ferns.

We apply a crown group defiition to Moniliformopses: Equisetum + ferns.

[edit] Refereces

• Friedman, WE, RC Moore & MD Puruggnan (2004), The evolution of plant development. Amer. J. Bot. 91: 1726–1741.
• Pryer, KM, H Schneider, AR Smith, R Cranfill, PG Wolf, JS Hunt & SD Sipes (2001), Horsetails and ferns are a monophyletic group and the closest living relatives to seed plants. Nature 409: 618-622.

[edit] Credits

ATW041216 (Palaeos com. Text public domain. No rights reserved.