Practice question

Psilotum nudum, commonly called whisk fern, represents morphologically highly reduced eusporangiate fern ally classified in Psilotaceae. Sporophyte consists of dichotomously branching green photosynthetic stems bearing small scale-like enations lacking vascular trace or lamina, performing photosynthesis due to absence of true leaves. True roots absent replaced by creeping rhizome with rhizoids and mycorrhizal association anchoring plant. Vascular tissue present as actinostelic protostele in aerial stems, synangia tri-lobed produce spores. Absence of leaves and roots interpreted as secondary reduction from leafy ancestors.