radicle

n. [ L. radicula, dim. of radix, -icis, root: cf. F. radicule. See Radix. ] (Bot.) (a) The rudimentary stem of a plant which supports the cotyledons in the seed, and from which the root is developed downward; the stem of the embryo; the caulicle. (b) A rootlet; a radicel. [ 1913 Webster ]