rhizoid (adj.)

word-forming element of Greek origin, used in botany and other sciences, meaning "root, root-like," from combining form of Greek rhiza "root," which is probably from PIE root *wrād- "branch, root." 

word-forming element meaning "like, like that of, thing like a ______," from Latinized form of Greek -oeidēs (three syllables), from eidos "form," related to idein "to see," eidenai "to know;" literally "to see" (from PIE *weid-es-, from root *weid- "to see"). The -o- is connective or a stem vowel from the previous element. Often implying an incomplete or imperfect resemblance to the thing indicated.

Proto-Indo-European root meaning "branch, root."

It forms all or part of: deracinate; eradicate; eradication; irradicable; licorice; radical; radicant; radicle; radicular; radish; ramada; ramify; ramus; rhizoid; rhizome; rhizophagous; root; rutabaga; wort.

It is the hypothetical source of/evidence for its existence is provided by: Greek rhiza, Lesbian brisda "root," Greek hradamnos "branch;" Latin radix) "root, radish;" Gothic waurts, Old English wyrt; Welsh gwraidd, Old Irish fren "root."