plant structure rhizoid 2011-05-04T03:03:32Z A plant structure (PO:0009011) that is a uniseriate filament with positive geotropism that grows from an epidermis (PO:0005679) or protonema (PO:0030003). May be unicellular or multicellular. Serves to anchor the plant to the substrate, and may function in nutrient and water uptake. Usually lacks chlorophyll. Includes epidermal rhizoids that grow from the epidermis of bryophytes and pteridophytes in the gametophytic phase or from the stems of some monocots, protonemal rhizoids that branch from a protonema, and rhizoids that develop from a basal cell of a gametophore bud. PO:0030078 PO_GIT:347 plant_anatomy rizoide (Spanish, exact) rwalls 仮根 (Japanese, exact)