The Nematophytes are a paraphyletic group of land organisms, probably including some plants as well as algae. They are known only from the fossil record, from the Silurian period until the early Devonian Rhynie chert.
The lack of a clear definition of the nematophytes has led to it being used as a wastebasket taxon. All manner of tubes and cell-patterned cuticles from the Silurian are called "nematophytic".