rhizoid

Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be unicellular or multicellular.

== Evolutionary development == Plants originated in aquatic environments and gradually migrated to land during their long course of evolution. In water or near it, plants could absorb water from their surroundings, with no need for any special absorbing organ or tissue. Additionally, in the primitive states of plant development, tissue differentiation and division of labor were minimal, thus specialized water-absorbing tissue was not required. The development of specialized tissues to absorb water efficiently and anchor the plant body to the ground enabled the spread of plants onto land.