Psilophyta

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Psilophyta A phylum of primitive tracheophyte plants that contains two extant genera – Psilotum (whisk ferns) and Tmesipteris – as well as numerous extinct forms that flourished in the Devonian period. Psilophytes have rhizoids rather than roots; the stems, which show dichotomous branching, may be naked or bear scalelike leaves.