PhylumPhylum
The phylum Pterophyta is a group of non-seed plants with a fossil record dating back to the lower Devonian. The phylum consists of about 11,000 living species.
Vegetatatively,the Pterophyta are a diverse group of plants with true leaves, roots and stems. Leaves are macrophylls and, in many families, demonstrate circinate vernation (a pattern of uncoiling of a crozier-like structure due to uneven growth). While arborescent species exist, no living fern demonstrates true secondary growth. Roots are adventitious.
Reproductively,
the Pterophyta also vary; they may be either homosporous and exosporic
or heterosporous and endosporic. Homospory with the production
of photosythetic free-living gametophytes is the most common
pattern. The structure of the spore, sporangium and sorus
are all important taxonomic features.
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