Rhyniophyte

A rhyniophyte is an extinct early vascular plant with branching, usually leafless stems and sporangia at their tips. Fossils from the Early Devonian preserve some of the earliest known vascular-plant body plans.

Vascular plant: A plant with specialized tissues that transport water and dissolved substances through its body. Rhyniophytes are among the earliest fossil plants with vascular tissue.
Rhynia: An extinct Early Devonian vascular plant known from exceptionally preserved fossils at Rhynie, Scotland. Its branching stems and terminal sporangia became the archetypal rhyniophyte form.
Early Devonian: The first age of the Devonian Period, spanning about 419 to 393 million years ago. Many defining rhyniophyte fossils date from this interval.
Lycophyte: A vascular plant lineage characterized by microphyll leaves and distinctive spore-producing structures. Lycophytes developed leaves, unlike the typically leafless rhyniophyte body plan.
Xylem: Plant tissue that conducts water and minerals and often provides structural support. Xylem occurs in the preserved central conducting strands of several rhyniophytes.
Aglaophyton: An extinct plant from the Rhynie chert with branching axes and terminal sporangia. It was once grouped with rhyniophytes, but its conducting tissue lacks convincing tracheids.
Silurian period: A geological period preceding the Devonian, spanning about 444 to 419 million years ago. The earliest vascular plants emerged before the best-known rhyniophyte fossils.
Bryophyte: A nonvascular land plant group including mosses, liverworts, and hornworts. Bryophytes lack the vascular tissues that define rhyniophytes.
Phloem: Plant tissue that transports sugars and other organic compounds through a plant. Phloem is part of the vascular system inferred in early plants such as rhyniophytes.
Horneophyton: An extinct Early Devonian plant with branching axes and distinctive terminal sporangia. Its unusual anatomy complicates simple definitions of rhyniophytes.

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