Polypodiaceae s.l.
("Ferns")
Habit
- terrestrial perennials
Stems
- usually subterranean, many horizontal
(rhizomatous)
Leaves
- usually large,
pinnately
lobed or 1-3x
compound;
circinate vernation
Sporangia
- all alike
(homosporous) rarely
heterosporous (floating aquatics); usu. aggregated in
clusters
(sori) on
abaxial
(lower) side of leaves, and covered by flap or tissue
(indusium)
or
leaf margin
(false
indusium)
Spores
- 8x, usually not green, smooth or sculptured
Diversity
- 7-30 families / ca. 200 genera / 7,500 species
Distribution
- cosmopolitan but most species rich in tropical mountains; most AZ species found in desert
Economics
- "fiddleheads" used as pot herbs; many species are ornamentals
Notes
- Eusporangiate ferns (Ophioglossaceae & Marattiaceae) possibly sister to
Psilotaceae. Leptosporangiate ferns (all others) supported as
monophyletic
but most "families" are
para/
polyphyletic
(exceptions Aspleniaceae, Salviniaceae, Marsiliaceae, Azollaceae).
Images
footer