Cladistics
While it is generally accepted that the leptosporangiate ferns are monophyletic, it is considered to be likely that the eusporangiate ferns, as a group, are polyphyletic. In each of the three examples from recently published studies, shown in the following table, it can be seen that, together, the four eusporangiate fern families do not form a single clade.
Pryer & Schuettpelz, 2009 |
ferns |
|
|
|
Ophioglossaceae
|
|
|
Psilotaceae
|
|
|
|
|
|
|
|
|
Equisetaceae
|
|
|
Marattiaceae
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rai & Graham, 2010 |
ferns |
|
|
|
|
|
|
Ophioglossaceae
|
|
|
Psilotaceae
|
|
|
|
|
|
Marattiaceae
|
|
|
Leptosporangiate
ferns
|
|
|
|
|
|
|
|
|
|
|
Lehtonen, 2011 |
ferns |
|
|
|
Ophioglossaceae
|
|
|
Psilotaceae
|
|
|
|
|
|
|
|
|
|
|
|
Equisetaceae
|
|
|
Leptosporangiate
ferns
|
|
|
|
|
|
|
|
|
|