Holdfast (biology)

[1] Holdfasts vary in shape and form depending on both the species and the substrate type.

The holdfasts of organisms that live in muddy substrates often have complex tangles of root-like growths.

These projections are called haptera and similar structures of the same name are found on lichens.

The holdfasts of organisms that live in sandy substrates are bulb-like and very flexible, such as those of sea pens, thus permitting the organism to pull the entire body into the substrate when the holdfast is contracted.

The claw-like holdfasts of kelps and other algae differ from the roots of land plants, in that they have no absorbent function, instead serving only as an anchor.