Fern Life Cycle

Also called

fern · pteridophyta · sorus · sori · sporangium · spore · prothallus · gametophyte · sporophyte · antheridium · archegonium · alternation of generations · swimming sperm · cryptogams · फर्न · बीजाणु · प्रोथैलस

Topics

• The fern we see is the sporophyte; the brown dots (sori) under its fronds are clusters of sporangia.
• Each sporangium has a ring of thick-walled cells, the annulus; as it dries it snaps back and flings the spores out.
• A spore that lands on moist soil grows into a tiny heart-shaped plate, the prothallus; this is the gametophyte.
• On the underside of the prothallus, antheridia make sperm and archegonia each hold one egg.
• The sperm can only swim, so ferns need a film of water for fertilisation; this ties them to damp places.
• The fertilised egg grows into a new sporophyte, which at first feeds on the prothallus and then roots on its own.
• Ferns are cryptogams: hidden reproductive organs and spores instead of seeds, but with true vascular tissue.
• The fern life cycle alternates between a spore-making plant and a gamete-making plant: alternation of generations.

About this model

A GLB file of about 333 KB, shown in Lably's 3D viewer and, on a phone, placed in your room with AR. Credit: Model, science and animation: Lably (built procedurally with three.js; no downloaded meshes). | CC BY 4.0. Original geometry and animation made for Lably.

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