rhizine
/ˈrʌɪziːn/(also rhizina) Botany
noun
A root-like structure consisting of a hypha or a group of hyphae, located on the underside of the thallus of a foliose lichen and serving to anchor it to the substrate.
Origin
Mid 19th century; earliest use found in John Lindley (1799–1865), botanist and horticulturist. From scientific Latin rhizina from ancient Greek ῥίζα root + classical Latin -ina.