Editing Frond (section)

== Non-pinnate fronds==
Some fronds are not pinnately compound (or simple), but may be [[leaf shape|palmate]], costapalmate, or [[wikt:bifurcation|bifurcate]]. 

There is a spectrum from costapalmate to palmate. Costapalmate fronds are shaped like the palm of a hand and have a short midrib or costa. Palmate fronds are also shaped like the palm of the hand, but all ribs or leaflets arise from a central area. A hastula is a flap of tissue borne at the insertion of the blade on the petiole on the upper, lower, or both leaf surfaces<ref>{{Cite web|url=http://w3.biosci.utexas.edu/prc/DigFlora/Waller/costapalmate.html|title=Costapalmate|website=w3.biosci.utexas.edu|access-date=2019-12-05}}</ref><ref>{{Cite book|title=Genera palmarum : the evolution and classification of the palms|last=Dransfield, John.|date=2008|publisher=Kew Publishing|isbn=978-1-84246-182-2|oclc=890586925}}</ref>

Bifurcate fronds may also develop. The extinct [[Devonian]] [[Spermatophyte|seed plant]] ''Cosmosperma polyloba'' demonstrated the early evolutionary diversification of frond branching patterns, presenting both bifurcate and trifurcate types.<ref>{{Cite journal|last1=Liu|first1=Le|last2=Wang|first2=Deming|last3=Meng|first3=Meicen|last4=Xue|first4=Jinzhuang|date=2017-12-01|title=Further study of Late Devonian seed plant Cosmosperma polyloba: Its reconstruction and evolutionary significance|journal=BMC Evolutionary Biology|volume=17|issue=1|pages=149|doi=10.1186/s12862-017-0992-1|pmid=28651518|pmc=5485708 |doi-access=free }}</ref>

Some ferns, like members of the group [[Ophioglossales]] have a unique arrangement -- such as a single fleshy or amorphous leaf.

[[image:fern frond pinnate.jpg|left|thumb|300px|Adaxial (left) and abaxial (right) surfaces of a pinnate fern frond (''[[Blechnum appendiculatum]]''). Sori are evident on the abaxial surface.]]