Ferns belong to the largest division of the
seedless vascular plants. They are widely distributed and can be
found in any habitat that flowering plants grow. The ferns we see are mature sporophytes:
they reproduce by spores through alternation of generations.
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Illustration of a compound frond and 2 fiddleheads.
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Fronds: |
leaves of ferns. sizes vary greatly. |
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Vegetative fronds: sterile fronds. |
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Fertile fronds: fronds that have sori. |
| Stipe: |
the petiole of a fern frond. |
| Rachis: |
an extension of the petiole of a compound fern frond. |
| Pinnae: |
(single: pinna). Leaflets of a pinnate frond. |
| Pinnules: |
the individual final divisions of a leaflet. |
"Fiddlehead": the coiled young leaves of a fern.
This unique morphological feature is called circinate vernation and is mediated by the hormone auxin. It is a characteristic
of fern leaf development.
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