Early gametophytes (a in figure) are more complex than in living
plants and have branched stems bearing sexual organs on terminal cupor
shield-shaped structures (Fig. 2a). Archegonia (female gametangia)
are flask-shaped with a neck canal and egg chamber, and are sunken as
in hornworts and most vascular plants (Fig. 2c). Antheridia (male
gametangia) are roughly spherical, sessile or with a poorly-defined
stalk, and superficial (Fig. 2b). Gametophytes are very similar to
associated sporophytes, and shared anatomical features (waterconducting
tissues, epidermal patterns, and stomates) have been used
to link corresponding elements of the life cycle18,20. Our provisional
reconstruction of the life cycle of an early vascular plant is based on
information from anatomically preserved plants and contemporaneous
compression fossils.
Early gametophytes (a in figure) are more complex than in livingplants and have branched stems bearing sexual organs on terminal cuporshield-shaped structures (Fig. 2a). Archegonia (female gametangia)are flask-shaped with a neck canal and egg chamber, and are sunken asin hornworts and most vascular plants (Fig. 2c). Antheridia (malegametangia) are roughly spherical, sessile or with a poorly-definedstalk, and superficial (Fig. 2b). Gametophytes are very similar toassociated sporophytes, and shared anatomical features (waterconductingtissues, epidermal patterns, and stomates) have been usedto link corresponding elements of the life cycle18,20. Our provisionalreconstruction of the life cycle of an early vascular plant is based oninformation from anatomically preserved plants and contemporaneouscompression fossils.
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