Psilotophyta

Psilotophyta (the so-called "whisk ferns") is a division (ie. phylum) of the kingdom Plantae. It is also called Psilophyta.

It contains only two genera: Psilotum is a small shrubby plant of the dry tropics, and Tmesipteris is an epiphyte of Australia, New Zealand, and New Caledonia. For many years, there has been controversy about the relationships of the Psilotophyta, with some claiming that they are ferns (Pterophyta), and others maintaining that they are descendants of the first vascular plants. Recent evidence from DNA suggests an affinity to the ferns.

There are a few characteristics which all Psilotophyta share. Psilotophyta are all vascular plants. They lack leaves, instead having small outgrowths called enations. The enations are considered not leaves because there is only a vascular bundle just underneath them, but not inside them, as leaves have. Psilotophyta also don't have roots. They are anchored by rhizoids. Absorption is aided by fungi called mycorrhizae. Three sporangia are united into a synangium, which is considered to be a very reduced series of branches. There is a thick tapetum to nourish to developing spores, as is typical of eusporangiate plants. The gametophyte looks like a little piece of subterranean stem, but produces antheridia and archegonia.